diff --git a/net/tcp/tcp_timer.c b/net/tcp/tcp_timer.c
index 568743e251308..1e6c9f9fb8312 100644
--- a/net/tcp/tcp_timer.c
+++ b/net/tcp/tcp_timer.c
@@ -599,7 +599,8 @@ void tcp_timer(FAR struct net_driver_s *dev, FAR struct tcp_conn_s *conn)
 
               /* Exponential backoff. */
 
-              conn->timer = TCP_RTO << (conn->nrtx > 4 ? 4: conn->nrtx);
+              conn->rto = TCP_RTO << (conn->nrtx > 4 ? 4: conn->nrtx);
+              tcp_update_retrantimer(conn, conn->rto);
               conn->nrtx++;
 
               /* Ok, so we need to retransmit. We do this differently