diff --git a/Makefile.am b/Makefile.am
index c15f9c55..f259015d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -222,12 +222,13 @@ unit_test_util_SOURCES = unit/test-util.c src/util.c
 unit_test_util_LDADD = @GLIB_LIBS@
 unit_objects += $(unit_test_utils_OBJECTS)
 
-unit_test_sms_SOURCES = unit/test-sms.c src/util.c src/smsutil.c
+unit_test_sms_SOURCES = unit/test-sms.c src/util.c src/smsutil.c src/storage.c
 unit_test_sms_LDADD = @GLIB_LIBS@
 unit_objects += $(unit_test_sms_OBJECTS)
 
 unit_test_simutil_SOURCES = unit/test-simutil.c src/util.c \
-						src/simutil.c src/smsutil.c
+						src/simutil.c src/smsutil.c \
+						src/storage.c
 unit_test_simutil_LDADD = @GLIB_LIBS@
 unit_objects += $(unit_test_simutil_OBJECTS)
 
diff --git a/src/common.c b/src/common.c
index ff94fc0e..63884a3a 100644
--- a/src/common.c
+++ b/src/common.c
@@ -26,6 +26,7 @@
 #define _GNU_SOURCE
 #include <string.h>
 #include <ctype.h>
+#include <errno.h>
 
 #include <glib.h>
 
diff --git a/src/sms.c b/src/sms.c
index fe765808..149ecd0a 100644
--- a/src/sms.c
+++ b/src/sms.c
@@ -57,6 +57,9 @@ struct ofono_sms {
 	gint tx_source;
 	struct ofono_message_waiting *mw;
 	unsigned int mw_watch;
+	struct ofono_sim *sim;
+	unsigned int sim_watch;
+	unsigned int imsi_watch;
 	const struct ofono_sms_driver *driver;
 	void *driver_data;
 	struct ofono_atom *atom;
@@ -785,6 +788,17 @@ static void sms_unregister(struct ofono_atom *atom)
 		__ofono_modem_remove_atom_watch(modem, sms->mw_watch);
 		sms->mw_watch = 0;
 	}
+
+	if (sms->sim_watch) {
+		if (sms->imsi_watch) {
+			ofono_sim_remove_ready_watch(sms->sim,
+							sms->imsi_watch);
+			sms->imsi_watch = 0;
+		}
+
+		__ofono_modem_remove_atom_watch(modem, sms->sim_watch);
+		sms->sim_watch = 0;
+	}
 }
 
 static void sms_remove(struct ofono_atom *atom)
@@ -836,7 +850,6 @@ struct ofono_sms *ofono_sms_create(struct ofono_modem *modem,
 
 	sms->sca.type = 129;
 	sms->ref = 1;
-	sms->assembly = sms_assembly_new();
 	sms->txq = g_queue_new();
 	sms->atom = __ofono_modem_add_atom(modem, OFONO_ATOM_TYPE_SMS,
 						sms_remove, sms);
@@ -870,12 +883,45 @@ static void mw_watch(struct ofono_atom *atom,
 	sms->mw = __ofono_atom_get_data(atom);
 }
 
+static void sms_got_imsi(void *data)
+{
+	struct ofono_sms *sms = data;
+	const char *imsi = ofono_sim_get_imsi(sms->sim);
+
+	sms->assembly = sms_assembly_new(imsi);
+}
+
+static void sim_watch(struct ofono_atom *atom,
+			enum ofono_atom_watch_condition cond, void *data)
+{
+	struct ofono_sms *sms = data;
+
+	if (cond == OFONO_ATOM_WATCH_CONDITION_UNREGISTERED) {
+		sms->imsi_watch = 0;
+
+		if (sms->assembly) {
+			sms_assembly_free(sms->assembly);
+			sms->assembly = NULL;
+		}
+
+		return;
+	}
+
+	sms->sim = __ofono_atom_get_data(atom);
+	sms->imsi_watch = ofono_sim_add_ready_watch(sms->sim, sms_got_imsi,
+							sms, NULL);
+
+	if (ofono_sim_get_ready(sms->sim))
+		sms_got_imsi(sms);
+}
+
 void ofono_sms_register(struct ofono_sms *sms)
 {
 	DBusConnection *conn = ofono_dbus_get_connection();
 	struct ofono_modem *modem = __ofono_atom_get_modem(sms->atom);
 	const char *path = __ofono_atom_get_path(sms->atom);
 	struct ofono_atom *mw_atom;
+	struct ofono_atom *sim_atom;
 
 	if (!g_dbus_register_interface(conn, path,
 					SMS_MANAGER_INTERFACE,
@@ -899,6 +945,16 @@ void ofono_sms_register(struct ofono_sms *sms)
 	if (mw_atom && __ofono_atom_get_registered(mw_atom))
 		mw_watch(mw_atom, OFONO_ATOM_WATCH_CONDITION_REGISTERED, sms);
 
+	sms->sim_watch = __ofono_modem_add_atom_watch(modem,
+					OFONO_ATOM_TYPE_SIM,
+					sim_watch, sms, NULL);
+
+	sim_atom = __ofono_modem_find_atom(modem, OFONO_ATOM_TYPE_SIM);
+
+	if (sim_atom && __ofono_atom_get_registered(sim_atom))
+		sim_watch(sim_atom,
+				OFONO_ATOM_WATCH_CONDITION_REGISTERED, sms);
+
 	__ofono_atom_register(sms->atom, sms_unregister);
 }
 
diff --git a/src/smsutil.c b/src/smsutil.c
index 79d99669..966a016c 100644
--- a/src/smsutil.c
+++ b/src/smsutil.c
@@ -23,16 +23,38 @@
 #include <config.h>
 #endif
 
+#define _GNU_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <dirent.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
 #include <glib.h>
 
+#include "types.h"
+#include "common.h"
 #include "util.h"
+#include "storage.h"
 #include "smsutil.h"
 
 #define uninitialized_var(x) x = x
 
+#define SMS_BACKUP_MODE 0600
+#define SMS_BACKUP_PATH STORAGEDIR "/%s/sms"
+#define SMS_BACKUP_PATH_DIR SMS_BACKUP_PATH "/%s-%i-%i"
+#define SMS_BACKUP_PATH_FILE SMS_BACKUP_PATH_DIR "/%03i"
+
+#define SMS_ADDR_FMT "%21[0-9+*#]"
+
+static GSList *sms_assembly_add_fragment_backup(struct sms_assembly *assembly,
+					const struct sms *sms, time_t ts,
+					const struct sms_address *addr,
+					guint16 ref, guint8 max, guint8 seq,
+					gboolean backup);
+
 void extract_bcd_number(const unsigned char *buf, int len, char *out)
 {
 	static const char digit_lut[] = "0123456789*#abc\0";
@@ -2173,9 +2195,177 @@ char *sms_decode_text(GSList *sms_list)
 	return utf8;
 }
 
-struct sms_assembly *sms_assembly_new()
+static int sms_serialize(unsigned char *buf, const struct sms *sms)
 {
-	return g_new0(struct sms_assembly, 1);
+	int len, tpdu_len;
+
+	sms_encode(sms, &len, &tpdu_len, buf + 1);
+	buf[0] = tpdu_len;
+
+	return len;
+}
+
+static gboolean sms_deserialize(const unsigned char *buf,
+		struct sms *sms, int len)
+{
+	if (len < 1)
+		return FALSE;
+
+	return sms_decode(buf + 1, len - 1, FALSE, buf[0], sms);
+}
+
+static void sms_assembly_load(struct sms_assembly *assembly,
+				const struct dirent *dir)
+{
+	struct sms_address addr;
+	char straddr[sizeof(addr.address) + 1];
+	guint16 ref;
+	guint8 max;
+	guint8 seq;
+	char *path;
+	int len;
+	struct stat segment_stat;
+	struct dirent **segments;
+	char *endp;
+	int r;
+	int i;
+	unsigned char buf[177];
+	struct sms segment;
+
+	if (dir->d_type != DT_DIR)
+		return;
+
+	if (sscanf(dir->d_name, SMS_ADDR_FMT "-%hi-%hhi",
+				straddr, &ref, &max) < 3)
+		return;
+	sms_address_from_string(&addr, straddr);
+
+	path = g_strdup_printf(SMS_BACKUP_PATH "/%s",
+			assembly->imsi, dir->d_name);
+	len = scandir(path, &segments, NULL, versionsort);
+	g_free(path);
+
+	if (len < 0)
+		return;
+
+	for (i = 0; i < len; i++) {
+		if (segments[i]->d_type != DT_REG)
+			continue;
+
+		seq = strtol(segments[i]->d_name, &endp, 10);
+		if (*endp != '\0')
+			continue;
+
+		r = read_file(buf, sizeof(buf), SMS_BACKUP_PATH "/%s/%s",
+				assembly->imsi,
+				dir->d_name, segments[i]->d_name);
+		if (r < 0)
+			continue;
+
+		if (!sms_deserialize(buf, &segment, r))
+			continue;
+
+		path = g_strdup_printf(SMS_BACKUP_PATH "/%s/%s",
+				assembly->imsi,
+				dir->d_name, segments[i]->d_name);
+		r = stat(path, &segment_stat);
+		g_free(path);
+
+		if (r != 0)
+			continue;
+
+		if (sms_assembly_add_fragment_backup(assembly, &segment,
+						segment_stat.st_mtime,
+						&addr, ref, max, seq, FALSE)) {
+			/* This should not happen */
+		}
+	}
+
+	for (i = 0; i < len; i++)
+		free(segments[i]);
+
+	free(segments);
+}
+
+static gboolean sms_assembly_store(struct sms_assembly *assembly,
+				struct sms_assembly_node *node,
+				const struct sms *sms, guint8 seq)
+{
+	unsigned char buf[177];
+	int len;
+
+	if (!assembly->imsi)
+		return FALSE;
+
+	len = sms_serialize(buf, sms);
+
+	if (write_file(buf, len, SMS_BACKUP_MODE,
+				SMS_BACKUP_PATH_FILE, assembly->imsi,
+				sms_address_to_string(&node->addr),
+				node->ref, node->max_fragments, seq) != len)
+		return FALSE;
+
+	return TRUE;
+}
+
+static void sms_assembly_backup_free(struct sms_assembly *assembly,
+					struct sms_assembly_node *node)
+{
+	char *path;
+	int seq;
+
+	if (!assembly->imsi)
+		return;
+
+	for (seq = 0; seq < node->max_fragments; seq++) {
+		int offset = seq / 32;
+		int bit = 1 << (seq % 32);
+
+		if (node->bitmap[offset] & bit) {
+			path = g_strdup_printf(SMS_BACKUP_PATH_FILE,
+					assembly->imsi,
+					sms_address_to_string(&node->addr),
+					node->ref, node->max_fragments, seq);
+			unlink(path);
+			g_free(path);
+		}
+	}
+
+	path = g_strdup_printf(SMS_BACKUP_PATH_DIR, assembly->imsi,
+				sms_address_to_string(&node->addr),
+				node->ref, node->max_fragments);
+	rmdir(path);
+	g_free(path);
+}
+
+struct sms_assembly *sms_assembly_new(const char *imsi)
+{
+	struct sms_assembly *ret = g_new0(struct sms_assembly, 1);
+	char *path;
+	struct dirent **entries;
+	int len;
+
+	if (imsi) {
+		ret->imsi = imsi;
+
+		/* Restore state from backup */
+
+		path = g_strdup_printf(SMS_BACKUP_PATH, imsi);
+		len = scandir(path, &entries, NULL, alphasort);
+		g_free(path);
+
+		if (len < 0)
+			return ret;
+
+		while (len--) {
+			sms_assembly_load(ret, entries[len]);
+			free(entries[len]);
+		}
+
+		free(entries);
+	}
+
+	return ret;
 }
 
 void sms_assembly_free(struct sms_assembly *assembly)
@@ -2198,6 +2388,16 @@ GSList *sms_assembly_add_fragment(struct sms_assembly *assembly,
 					const struct sms *sms, time_t ts,
 					const struct sms_address *addr,
 					guint16 ref, guint8 max, guint8 seq)
+{
+	return sms_assembly_add_fragment_backup(assembly, sms,
+						ts, addr, ref, max, seq, TRUE);
+}
+
+static GSList *sms_assembly_add_fragment_backup(struct sms_assembly *assembly,
+					const struct sms *sms, time_t ts,
+					const struct sms_address *addr,
+					guint16 ref, guint8 max, guint8 seq,
+					gboolean backup)
 {
 	int offset = seq / 32;
 	int bit = 1 << (seq % 32);
@@ -2272,11 +2472,17 @@ out:
 	node->bitmap[offset] |= bit;
 	node->num_fragments += 1;
 
-	if (node->num_fragments < node->max_fragments)
+	if (node->num_fragments < node->max_fragments) {
+		if (backup)
+			sms_assembly_store(assembly, node, sms, seq);
+
 		return NULL;
+	}
 
 	completed = node->fragment_list;
 
+	sms_assembly_backup_free(assembly, node);
+
 	if (prev)
 		prev->next = l->next;
 	else
@@ -2310,6 +2516,8 @@ void sms_assembly_expire(struct sms_assembly *assembly, time_t before)
 			continue;
 		}
 
+		sms_assembly_backup_free(assembly, node);
+
 		g_slist_foreach(node->fragment_list, (GFunc)g_free, 0);
 		g_slist_free(node->fragment_list);
 		g_free(node);
diff --git a/src/smsutil.h b/src/smsutil.h
index 93cdf973..daccaf71 100644
--- a/src/smsutil.h
+++ b/src/smsutil.h
@@ -360,6 +360,7 @@ struct sms_assembly_node {
 };
 
 struct sms_assembly {
+	const char *imsi;
 	GSList *assembly_list;
 };
 
@@ -456,7 +457,7 @@ gboolean sms_extract_language_variant(const struct sms *sms, guint8 *locking,
 unsigned char *sms_decode_datagram(GSList *sms_list, long *out_len);
 char *sms_decode_text(GSList *sms_list);
 
-struct sms_assembly *sms_assembly_new();
+struct sms_assembly *sms_assembly_new(const char *imsi);
 void sms_assembly_free(struct sms_assembly *assembly);
 GSList *sms_assembly_add_fragment(struct sms_assembly *assembly,
 					const struct sms *sms, time_t ts,
diff --git a/unit/test-sms.c b/unit/test-sms.c
index b5617b59..85af3b89 100644
--- a/unit/test-sms.c
+++ b/unit/test-sms.c
@@ -623,7 +623,7 @@ static void test_assembly()
 	unsigned char pdu[164];
 	long pdu_len;
 	struct sms sms;
-	struct sms_assembly *assembly = sms_assembly_new();
+	struct sms_assembly *assembly = sms_assembly_new(NULL);
 	guint16 ref;
 	guint8 max;
 	guint8 seq;
@@ -780,7 +780,7 @@ static void test_prepare_concat()
 	struct sms *sms;
 	struct sms decoded;
 	int pdu_len, tpdu_len;
-	struct sms_assembly *assembly = sms_assembly_new();
+	struct sms_assembly *assembly = sms_assembly_new(NULL);
 	guint16 ref;
 	guint8 max;
 	guint8 seq;