diff --git a/include/polarssl/des.h b/include/polarssl/des.h
index 0dedf62..74d5acb 100644
--- a/include/polarssl/des.h
+++ b/include/polarssl/des.h
@@ -177,6 +177,7 @@
                     const unsigned char input[8],
                     unsigned char output[8] );
 
+#if defined(POLARSSL_CIPHER_MODE_CBC)
 /**
  * \brief          DES-CBC buffer encryption/decryption
  *
@@ -193,6 +194,7 @@
                     unsigned char iv[8],
                     const unsigned char *input,
                     unsigned char *output );
+#endif /* POLARSSL_CIPHER_MODE_CBC */
 
 /**
  * \brief          3DES-ECB block encryption/decryption
@@ -207,6 +209,7 @@
                      const unsigned char input[8],
                      unsigned char output[8] );
 
+#if defined(POLARSSL_CIPHER_MODE_CBC)
 /**
  * \brief          3DES-CBC buffer encryption/decryption
  *
@@ -225,6 +228,7 @@
                      unsigned char iv[8],
                      const unsigned char *input,
                      unsigned char *output );
+#endif /* POLARSSL_CIPHER_MODE_CBC */
 
 #ifdef __cplusplus
 }