diff --git a/ChangeLog b/ChangeLog
index 1fb1859..18116f7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -11,6 +11,8 @@
    * Fix resource leak on windows platform, in mbedtls_x509_crt_parse_path.
      In case of failure, when an error occures, goto cleanup.
      Found by redplait #590
+   * Add MBEDTLS_MPI_CHK to check for error value of mbedtls_mpi_fill_random.
+     Reported and fix suggested by guidovranken in #740
 
 = mbed TLS 2.1.8 branch released 2017-06-21
 
diff --git a/library/dhm.c b/library/dhm.c
index 0f4d316..dc72c53 100644
--- a/library/dhm.c
+++ b/library/dhm.c
@@ -162,7 +162,7 @@
      */
     do
     {
-        mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng );
+        MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) );
 
         while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 )
             MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) );
@@ -248,7 +248,7 @@
      */
     do
     {
-        mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng );
+        MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) );
 
         while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 )
             MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) );
@@ -321,7 +321,7 @@
     count = 0;
     do
     {
-        mbedtls_mpi_fill_random( &ctx->Vi, mbedtls_mpi_size( &ctx->P ), f_rng, p_rng );
+        MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->Vi, mbedtls_mpi_size( &ctx->P ), f_rng, p_rng ) );
 
         while( mbedtls_mpi_cmp_mpi( &ctx->Vi, &ctx->P ) >= 0 )
             MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->Vi, 1 ) );
diff --git a/library/ecp.c b/library/ecp.c
index 4722599..1d4f5cb 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -1072,7 +1072,7 @@
     /* Generate l such that 1 < l < p */
     do
     {
-        mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng );
+        MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng ) );
 
         while( mbedtls_mpi_cmp_mpi( &l, &grp->P ) >= 0 )
             MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &l, 1 ) );
@@ -1454,7 +1454,7 @@
     /* Generate l such that 1 < l < p */
     do
     {
-        mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng );
+        MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng ) );
 
         while( mbedtls_mpi_cmp_mpi( &l, &grp->P ) >= 0 )
             MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &l, 1 ) );