diff --git a/include/mbedtls/lms.h b/include/mbedtls/lms.h
index 1ba4f3a..40ab783 100644
--- a/include/mbedtls/lms.h
+++ b/include/mbedtls/lms.h
@@ -139,7 +139,7 @@
                                                      Boolean values only. */
 } mbedtls_lmots_public_t;
 
-#ifdef MBEDTLS_LMS_PRIVATE
+#if defined(MBEDTLS_LMS_PRIVATE)
 /** LMOTS private context structure.
  *
  * A LMOTS private key is one hash output for each of digit of the digest +
@@ -163,7 +163,7 @@
     unsigned char MBEDTLS_PRIVATE(have_private_key); /*!< Whether the context contains a private key.
                                                      Boolean values only. */
 } mbedtls_lmots_private_t;
-#endif /* MBEDTLS_LMS_PRIVATE */
+#endif /* defined(MBEDTLS_LMS_PRIVATE) */
 
 
 /** LMS parameters structure.
@@ -209,7 +209,7 @@
 } mbedtls_lms_public_t;
 
 
-#ifdef MBEDTLS_LMS_PRIVATE
+#if defined(MBEDTLS_LMS_PRIVATE)
 /** LMS private context structure.
  *
  * A LMS private key is a set of LMOTS private keys, an index to the next usable
@@ -237,7 +237,7 @@
     unsigned char MBEDTLS_PRIVATE(have_private_key); /*!< Whether the context contains a private key.
                                                      Boolean values only. */
 } mbedtls_lms_private_t;
-#endif /* MBEDTLS_LMS_PRIVATE */
+#endif /* defined(MBEDTLS_LMS_PRIVATE) */
 
 /**
  * \brief                    This function initializes an LMS public context
@@ -301,7 +301,7 @@
                         const unsigned char *msg, size_t msg_size,
                         const unsigned char *sig, size_t sig_size );
 
-#ifdef MBEDTLS_LMS_PRIVATE
+#if defined(MBEDTLS_LMS_PRIVATE)
 /**
  * \brief                    This function initializes an LMS private context
  *
@@ -434,7 +434,7 @@
                       int (*f_rng)(void *, unsigned char *, size_t),
                       void* p_rng, unsigned char *msg, unsigned int msg_size,
                       unsigned char *sig, size_t sig_size, size_t *sig_len );
-#endif /* MBEDTLS_LMS_PRIVATE */
+#endif /* defined(MBEDTLS_LMS_PRIVATE) */
 
 #ifdef __cplusplus
 }