diff --git a/include/mbedtls/des.h b/include/mbedtls/des.h
index 29b96db..a82ecf8 100644
--- a/include/mbedtls/des.h
+++ b/include/mbedtls/des.h
@@ -147,6 +147,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des_key_check_key_parity( const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
 /**
@@ -160,6 +161,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des_key_check_weak( const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
 /**
@@ -174,6 +176,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des_setkey_enc( mbedtls_des_context *ctx, const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
 /**
@@ -188,6 +191,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des_setkey_dec( mbedtls_des_context *ctx, const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
 /**
@@ -198,6 +202,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des3_set2key_enc( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 2] );
 
@@ -209,6 +214,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des3_set2key_dec( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 2] );
 
@@ -220,6 +226,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des3_set3key_enc( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 3] );
 
@@ -231,6 +238,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des3_set3key_dec( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 3] );
 
@@ -247,6 +255,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des_crypt_ecb( mbedtls_des_context *ctx,
                     const unsigned char input[8],
                     unsigned char output[8] );
@@ -274,6 +283,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des_crypt_cbc( mbedtls_des_context *ctx,
                     int mode,
                     size_t length,
@@ -291,6 +301,7 @@
  *
  * \return         0 if successful
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des3_crypt_ecb( mbedtls_des3_context *ctx,
                      const unsigned char input[8],
                      unsigned char output[8] );
@@ -316,6 +327,7 @@
  *
  * \return         0 if successful, or MBEDTLS_ERR_DES_INVALID_INPUT_LENGTH
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des3_crypt_cbc( mbedtls_des3_context *ctx,
                      int mode,
                      size_t length,
@@ -346,6 +358,7 @@
  *
  * \return         0 if successful, or 1 if the test failed
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des_self_test( int verbose );
 
 #endif /* MBEDTLS_SELF_TEST */