diff --git a/conn_id_manager.go b/conn_id_manager.go
index f4bc5c0e..ee1729a7 100644
--- a/conn_id_manager.go
+++ b/conn_id_manager.go
@@ -68,9 +68,9 @@ func (h *connIDManager) Add(f *wire.NewConnectionIDFrame) error {
 }
 
 func (h *connIDManager) add(f *wire.NewConnectionIDFrame) error {
-	// If the NEW_CONNECTION_ID frame is reordered, such that its sequence number
-	// was already retired, send the RETIRE_CONNECTION_ID frame immediately.
-	if f.SequenceNumber < h.highestRetired {
+	// If the NEW_CONNECTION_ID frame is reordered, such that its sequence number is smaller than the currently active
+	// connection ID or if it was already retired, send the RETIRE_CONNECTION_ID frame immediately.
+	if f.SequenceNumber <= h.activeSequenceNumber || f.SequenceNumber < h.highestRetired {
 		h.queueControlFrame(&wire.RetireConnectionIDFrame{
 			SequenceNumber: f.SequenceNumber,
 		})
diff --git a/conn_id_manager_test.go b/conn_id_manager_test.go
index 49345d19..3c3a6cfb 100644
--- a/conn_id_manager_test.go
+++ b/conn_id_manager_test.go
@@ -181,6 +181,26 @@ var _ = Describe("Connection ID Manager", func() {
 		Expect(frameQueue[0].(*wire.RetireConnectionIDFrame).SequenceNumber).To(BeEquivalentTo(4))
 	})
 
+	It("ignores reordered connection IDs, if their sequence number was already retired or less than active", func() {
+		Expect(m.Add(&wire.NewConnectionIDFrame{
+			SequenceNumber: 10,
+			ConnectionID:   protocol.ConnectionID{0xde, 0xad, 0xbe, 0xef},
+			RetirePriorTo:  5,
+		})).To(Succeed())
+		Expect(frameQueue).To(HaveLen(1))
+		Expect(frameQueue[0].(*wire.RetireConnectionIDFrame).SequenceNumber).To(BeZero())
+		frameQueue = nil
+		Expect(m.Get()).To(Equal(protocol.ConnectionID{0xde, 0xad, 0xbe, 0xef}))
+
+		Expect(m.Add(&wire.NewConnectionIDFrame{
+			SequenceNumber: 9,
+			ConnectionID:   protocol.ConnectionID{0xde, 0xca, 0xfb, 0xad},
+			RetirePriorTo:  5,
+		})).To(Succeed())
+		Expect(frameQueue).To(HaveLen(1))
+		Expect(frameQueue[0].(*wire.RetireConnectionIDFrame).SequenceNumber).To(BeEquivalentTo(9))
+	})
+
 	It("errors when the peer sends too connection IDs", func() {
 		for i := uint8(1); i < protocol.MaxActiveConnectionIDs; i++ {
 			Expect(m.Add(&wire.NewConnectionIDFrame{