diff --git a/include/mbedtls/des.h b/include/mbedtls/des.h
index 63a8e00..7bd618c 100644
--- a/include/mbedtls/des.h
+++ b/include/mbedtls/des.h
@@ -139,6 +139,7 @@
  *                 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] );
 
 /**
@@ -152,6 +153,7 @@
  *                 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] );
 
 /**
@@ -166,6 +168,7 @@
  *                 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] );
 
 /**
@@ -180,6 +183,7 @@
  *                 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] );
 
 /**
@@ -190,6 +194,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des3_set2key_enc( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 2] );
 
@@ -201,6 +206,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des3_set2key_dec( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 2] );
 
@@ -212,6 +218,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des3_set3key_enc( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 3] );
 
@@ -223,6 +230,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des3_set3key_dec( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 3] );
 
@@ -239,6 +247,7 @@
  *                 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] );
@@ -266,6 +275,7 @@
  *                 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,
@@ -283,6 +293,7 @@
  *
  * \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] );
@@ -308,6 +319,7 @@
  *
  * \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,
@@ -338,6 +350,7 @@
  *
  * \return         0 if successful, or 1 if the test failed
  */
+MBEDTLS_CHECK_RETURN
 int mbedtls_des_self_test( int verbose );
 
 #endif /* MBEDTLS_SELF_TEST */