diff --git a/mongoose.c b/mongoose.c
index e13bcf7c..50c99cd6 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -5238,7 +5238,8 @@ size_t mg_tls_pending(struct mg_connection *c) {
 long mg_tls_recv(struct mg_connection *c, void *buf, size_t len) {
   struct mg_tls *tls = (struct mg_tls *) c->tls;
   long n = mbedtls_ssl_read(&tls->ssl, (unsigned char *) buf, len);
-  if (n == MBEDTLS_ERR_SSL_WANT_READ) return MG_IO_WAIT;
+  if (n == MBEDTLS_ERR_SSL_WANT_READ || n == MBEDTLS_ERR_SSL_WANT_WRITE) 
+    return MG_IO_WAIT;
   if (n <= 0) return MG_IO_ERR;
   return n;
 }
@@ -5246,7 +5247,8 @@ long mg_tls_recv(struct mg_connection *c, void *buf, size_t len) {
 long mg_tls_send(struct mg_connection *c, const void *buf, size_t len) {
   struct mg_tls *tls = (struct mg_tls *) c->tls;
   long n = mbedtls_ssl_write(&tls->ssl, (unsigned char *) buf, len);
-  if (n == MBEDTLS_ERR_SSL_WANT_WRITE) return MG_IO_WAIT;
+  if (n == MBEDTLS_ERR_SSL_WANT_READ || n == MBEDTLS_ERR_SSL_WANT_WRITE)
+    return MG_IO_WAIT;
   if (n <= 0) return MG_IO_ERR;
   return n;
 }
diff --git a/src/tls_mbed.c b/src/tls_mbed.c
index 8caf4d65..edfa91a4 100644
--- a/src/tls_mbed.c
+++ b/src/tls_mbed.c
@@ -185,7 +185,8 @@ size_t mg_tls_pending(struct mg_connection *c) {
 long mg_tls_recv(struct mg_connection *c, void *buf, size_t len) {
   struct mg_tls *tls = (struct mg_tls *) c->tls;
   long n = mbedtls_ssl_read(&tls->ssl, (unsigned char *) buf, len);
-  if (n == MBEDTLS_ERR_SSL_WANT_READ) return MG_IO_WAIT;
+  if (n == MBEDTLS_ERR_SSL_WANT_READ || n == MBEDTLS_ERR_SSL_WANT_WRITE) 
+    return MG_IO_WAIT;
   if (n <= 0) return MG_IO_ERR;
   return n;
 }
@@ -193,7 +194,8 @@ long mg_tls_recv(struct mg_connection *c, void *buf, size_t len) {
 long mg_tls_send(struct mg_connection *c, const void *buf, size_t len) {
   struct mg_tls *tls = (struct mg_tls *) c->tls;
   long n = mbedtls_ssl_write(&tls->ssl, (unsigned char *) buf, len);
-  if (n == MBEDTLS_ERR_SSL_WANT_WRITE) return MG_IO_WAIT;
+  if (n == MBEDTLS_ERR_SSL_WANT_READ || n == MBEDTLS_ERR_SSL_WANT_WRITE)
+    return MG_IO_WAIT;
   if (n <= 0) return MG_IO_ERR;
   return n;
 }