diff --git a/docs/releases.md b/docs/releases.md
index 3f5a7b6c..935f5950 100644
--- a/docs/releases.md
+++ b/docs/releases.md
@@ -14,6 +14,7 @@ and the [ntfy Android app](https://github.com/binwiederhier/ntfy-android/release
 
 * Return HTTP 500 for GET /_matrix/push/v1/notify when base-url is not configured (no ticket)
 * Disallow setting `upstream-base-url` to the same value as `base-url` ([#334](https://github.com/binwiederhier/ntfy/issues/334), thanks to [@oester](https://github.com/oester) for reporting)
+* Fix `since=<id>` implementation for multiple topics ([#336](https://github.com/binwiederhier/ntfy/issues/336), thanks to [@karmanyaahm](https://github.com/karmanyaahm) for reporting)
 
 ## ntfy Android app v1.14.0 (UNRELEASED)
 
diff --git a/server/message_cache.go b/server/message_cache.go
index 77aa4f78..afd4bf17 100644
--- a/server/message_cache.go
+++ b/server/message_cache.go
@@ -49,7 +49,7 @@ const (
 		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
 	`
 	pruneMessagesQuery           = `DELETE FROM messages WHERE time < ? AND published = 1`
-	selectRowIDFromMessageID     = `SELECT id FROM messages WHERE topic = ? AND mid = ?`
+	selectRowIDFromMessageID     = `SELECT id FROM messages WHERE mid = ?` // Do not include topic, see #336 and TestServer_PollSinceID_MultipleTopics
 	selectMessagesSinceTimeQuery = `
 		SELECT mid, time, topic, message, title, priority, tags, click, actions, attachment_name, attachment_type, attachment_size, attachment_expires, attachment_url, sender, encoding
 		FROM messages 
@@ -294,7 +294,7 @@ func (c *messageCache) messagesSinceTime(topic string, since sinceMarker, schedu
 }
 
 func (c *messageCache) messagesSinceID(topic string, since sinceMarker, scheduled bool) ([]*message, error) {
-	idrows, err := c.db.Query(selectRowIDFromMessageID, topic, since.ID())
+	idrows, err := c.db.Query(selectRowIDFromMessageID, since.ID())
 	if err != nil {
 		return nil, err
 	}
diff --git a/server/server.go b/server/server.go
index dacfa743..4d028d91 100644
--- a/server/server.go
+++ b/server/server.go
@@ -16,6 +16,7 @@ import (
 	"path"
 	"path/filepath"
 	"regexp"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -972,19 +973,26 @@ func parseSubscribeParams(r *http.Request) (poll bool, since sinceMarker, schedu
 	return
 }
 
+// sendOldMessages selects old messages from the messageCache and calls sub for each of them. It uses since as the
+// marker, returning only messages that are newer than the marker.
 func (s *Server) sendOldMessages(topics []*topic, since sinceMarker, scheduled bool, v *visitor, sub subscriber) error {
 	if since.IsNone() {
 		return nil
 	}
+	messages := make([]*message, 0)
 	for _, t := range topics {
-		messages, err := s.messageCache.Messages(t.ID, since, scheduled)
+		topicMessages, err := s.messageCache.Messages(t.ID, since, scheduled)
 		if err != nil {
 			return err
 		}
-		for _, m := range messages {
-			if err := sub(v, m); err != nil {
-				return err
-			}
+		messages = append(messages, topicMessages...)
+	}
+	sort.Slice(messages, func(i, j int) bool {
+		return messages[i].Time < messages[j].Time
+	})
+	for _, m := range messages {
+		if err := sub(v, m); err != nil {
+			return err
 		}
 	}
 	return nil
diff --git a/server/server_test.go b/server/server_test.go
index 66ad6e1b..9fc9aa88 100644
--- a/server/server_test.go
+++ b/server/server_test.go
@@ -437,6 +437,53 @@ func TestServer_PublishAndPollSince(t *testing.T) {
 	require.Equal(t, 40008, toHTTPError(t, response.Body.String()).Code)
 }
 
+func newMessageWithTimestamp(topic, message string, timestamp int64) *message {
+	m := newDefaultMessage(topic, message)
+	m.Time = timestamp
+	return m
+}
+
+func TestServer_PollSinceID_MultipleTopics(t *testing.T) {
+	s := newTestServer(t, newTestConfig(t))
+
+	require.Nil(t, s.messageCache.AddMessage(newMessageWithTimestamp("mytopic1", "test 1", 1655740277)))
+	markerMessage := newMessageWithTimestamp("mytopic2", "test 2", 1655740283)
+	require.Nil(t, s.messageCache.AddMessage(markerMessage))
+	require.Nil(t, s.messageCache.AddMessage(newMessageWithTimestamp("mytopic1", "test 3", 1655740289)))
+	require.Nil(t, s.messageCache.AddMessage(newMessageWithTimestamp("mytopic2", "test 4", 1655740293)))
+	require.Nil(t, s.messageCache.AddMessage(newMessageWithTimestamp("mytopic1", "test 5", 1655740297)))
+	require.Nil(t, s.messageCache.AddMessage(newMessageWithTimestamp("mytopic2", "test 6", 1655740303)))
+
+	response := request(t, s, "GET", fmt.Sprintf("/mytopic1,mytopic2/json?poll=1&since=%s", markerMessage.ID), "", nil)
+	messages := toMessages(t, response.Body.String())
+	require.Equal(t, 4, len(messages))
+	require.Equal(t, "test 3", messages[0].Message)
+	require.Equal(t, "mytopic1", messages[0].Topic)
+	require.Equal(t, "test 4", messages[1].Message)
+	require.Equal(t, "mytopic2", messages[1].Topic)
+	require.Equal(t, "test 5", messages[2].Message)
+	require.Equal(t, "mytopic1", messages[2].Topic)
+	require.Equal(t, "test 6", messages[3].Message)
+	require.Equal(t, "mytopic2", messages[3].Topic)
+}
+
+func TestServer_PollSinceID_MultipleTopics_IDDoesNotMatch(t *testing.T) {
+	s := newTestServer(t, newTestConfig(t))
+
+	require.Nil(t, s.messageCache.AddMessage(newMessageWithTimestamp("mytopic1", "test 3", 1655740289)))
+	require.Nil(t, s.messageCache.AddMessage(newMessageWithTimestamp("mytopic2", "test 4", 1655740293)))
+	require.Nil(t, s.messageCache.AddMessage(newMessageWithTimestamp("mytopic1", "test 5", 1655740297)))
+	require.Nil(t, s.messageCache.AddMessage(newMessageWithTimestamp("mytopic2", "test 6", 1655740303)))
+
+	response := request(t, s, "GET", "/mytopic1,mytopic2/json?poll=1&since=NoMatchForID", "", nil)
+	messages := toMessages(t, response.Body.String())
+	require.Equal(t, 4, len(messages))
+	require.Equal(t, "test 3", messages[0].Message)
+	require.Equal(t, "test 4", messages[1].Message)
+	require.Equal(t, "test 5", messages[2].Message)
+	require.Equal(t, "test 6", messages[3].Message)
+}
+
 func TestServer_PublishViaGET(t *testing.T) {
 	s := newTestServer(t, newTestConfig(t))