diff --git a/src/api/api_lib.c b/src/api/api_lib.c
index 94aa0dc0..02d284b1 100644
--- a/src/api/api_lib.c
+++ b/src/api/api_lib.c
@@ -496,10 +496,13 @@ netconn_recv(struct netconn *conn)
     }
     
     sys_mbox_fetch(conn->recvmbox, (void **)&p);
-	conn->recv_avail -= p->tot_len;
-    /* Register event with callback */
-    if (conn->callback)
+
+    if (p != NULL) {
+      conn->recv_avail -= p->tot_len;
+      /* Register event with callback */
+      if (conn->callback)
         (*conn->callback)(conn, NETCONN_EVT_RCVMINUS, p->tot_len);
+    }
 
     /* If we are closed, we indicate that we no longer wish to recieve
        data by setting conn->recvmbox to SYS_MBOX_NULL. */
diff --git a/src/api/api_msg.c b/src/api/api_msg.c
index 83cd80ab..c3b84375 100644
--- a/src/api/api_msg.c
+++ b/src/api/api_msg.c
@@ -51,11 +51,14 @@ recv_tcp(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
   }
 
   if(conn->recvmbox != SYS_MBOX_NULL) {
+    	  
     conn->err = err;
-	conn->recv_avail += p->tot_len;
-    /* Register event with callback */
-    if (conn->callback)
+    if (p != NULL) {
+      conn->recv_avail += p->tot_len;
+      /* Register event with callback */
+      if (conn->callback)
         (*conn->callback)(conn, NETCONN_EVT_RCVPLUS, p->tot_len);
+    }  
     sys_mbox_post(conn->recvmbox, p);
   }  
   return ERR_OK;