diff --git a/src/shared/ad.c b/src/shared/ad.c
index d8b124d..90d27e3 100644
--- a/src/shared/ad.c
+++ b/src/shared/ad.c
@@ -464,6 +464,11 @@ bool bt_ad_add_manufacturer_data(struct bt_ad *ad, uint16_t manufacturer_id,
 
 	new_data->len = len;
 
+	if (bt_ad_has_manufacturer_data(ad, new_data)) {
+		manuf_destroy(new_data);
+		return false;
+	}
+
 	if (queue_push_tail(ad->manufacturer_data, new_data))
 		return true;
 
@@ -472,6 +477,32 @@ bool bt_ad_add_manufacturer_data(struct bt_ad *ad, uint16_t manufacturer_id,
 	return false;
 }
 
+static bool manufacturer_data_match(const void *data, const void *user_data)
+{
+	const struct bt_ad_manufacturer_data *m1 = data;
+	const struct bt_ad_manufacturer_data *m2 = data;
+
+	if (m1->manufacturer_id != m2->manufacturer_id)
+		return false;
+
+	if (m1->len != m2->len)
+		return false;
+
+	return !memcmp(m1->data, m2->data, m1->len);
+}
+
+bool bt_ad_has_manufacturer_data(struct bt_ad *ad,
+				const struct bt_ad_manufacturer_data *data)
+{
+	if (!ad)
+		return false;
+
+	if (!data)
+		return !queue_isempty(ad->manufacturer_data);
+
+	return queue_find(ad->manufacturer_data, manufacturer_data_match, data);
+}
+
 void bt_ad_foreach_manufacturer_data(struct bt_ad *ad, bt_ad_func_t func,
 							void *user_data)
 {
diff --git a/src/shared/ad.h b/src/shared/ad.h
index 6e916a3..b7d9ade 100644
--- a/src/shared/ad.h
+++ b/src/shared/ad.h
@@ -50,6 +50,9 @@ void bt_ad_clear_service_uuid(struct bt_ad *ad);
 bool bt_ad_add_manufacturer_data(struct bt_ad *ad, uint16_t manufacturer_data,
 						void *data, size_t len);
 
+bool bt_ad_has_manufacturer_data(struct bt_ad *ad,
+				const struct bt_ad_manufacturer_data *data);
+
 void bt_ad_foreach_manufacturer_data(struct bt_ad *ad, bt_ad_func_t func,
 							void *user_data);