diff --git a/ChangeLog b/ChangeLog
index ddd56732c7f5..0646e6c4cf84 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -19,6 +19,8 @@ Bugfix
      curves as well as RSA. Fixes #777 found by dbedev.
    * Fix for redefinition of _WIN32_WINNT to avoid overriding a definition
      used by user applications. Found and fixed by Fabio Alessandrelli.
+   * Fix compilation warnings with IAR toolchain, on 32 bit platform.
+     Reported by rahmanih in #683
 
 Changes
    * Changed CMake defaults for IAR to treat all compiler warnings as errors.
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index eb19f58c0f11..0ccab588eb18 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -2888,7 +2888,7 @@ static int ssl_prepare_server_key_exchange( mbedtls_ssl_context *ssl,
     if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
     {
         int ret;
-        size_t len;
+        size_t len = 0;
 
         ret = mbedtls_ecjpake_write_round_two(
             &ssl->handshake->ecjpake_ctx,
@@ -2928,7 +2928,7 @@ static int ssl_prepare_server_key_exchange( mbedtls_ssl_context *ssl,
     if( mbedtls_ssl_ciphersuite_uses_dhe( ciphersuite_info ) )
     {
         int ret;
-        size_t len;
+        size_t len = 0;
 
         if( ssl->conf->dhm_P.p == NULL || ssl->conf->dhm_G.p == NULL )
         {
@@ -2993,7 +2993,7 @@ static int ssl_prepare_server_key_exchange( mbedtls_ssl_context *ssl,
         const mbedtls_ecp_curve_info **curve = NULL;
         const mbedtls_ecp_group_id *gid;
         int ret;
-        size_t len;
+        size_t len = 0;
 
         /* Match our preference list against the offered curves */
         for( gid = ssl->conf->curve_list; *gid != MBEDTLS_ECP_DP_NONE; gid++ )