diff --git a/library/md.c b/library/md.c
index df010ae27..882942e13 100644
--- a/library/md.c
+++ b/library/md.c
@@ -529,9 +529,14 @@ int mbedtls_md_hmac_starts( mbedtls_md_context_t *ctx, const unsigned char *key,
 
     mbedtls_md_handle_t md_info;
 
-    if( ctx == NULL || ctx->hmac_ctx == NULL )
+    if( ctx == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
+#if !defined(MBEDTLS_MD_SINGLE_HASH)
+    if( ctx->hmac_ctx == NULL )
+        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
+#endif /* !MBEDTLS_MD_SINGLE_HASH */
+
     md_info = mbedtls_md_get_handle( ctx );
     if( md_info == MBEDTLS_MD_INVALID_HANDLE )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
@@ -587,9 +592,14 @@ int mbedtls_md_hmac_update( mbedtls_md_context_t *ctx,
 {
     mbedtls_md_handle_t md_info;
 
-    if( ctx == NULL || ctx->hmac_ctx == NULL )
+    if( ctx == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
+#if !defined(MBEDTLS_MD_SINGLE_HASH)
+    if( ctx->hmac_ctx == NULL )
+        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
+#endif /* !MBEDTLS_MD_SINGLE_HASH */
+
     md_info = mbedtls_md_get_handle( ctx );
     if( md_info == MBEDTLS_MD_INVALID_HANDLE )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
@@ -607,9 +617,14 @@ int mbedtls_md_hmac_finish( mbedtls_md_context_t *ctx, unsigned char *output )
 
     mbedtls_md_handle_t md_info;
 
-    if( ctx == NULL || ctx->hmac_ctx == NULL )
+    if( ctx == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
+#if !defined(MBEDTLS_MD_SINGLE_HASH)
+    if( ctx->hmac_ctx == NULL )
+        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
+#endif /* !MBEDTLS_MD_SINGLE_HASH */
+
     md_info = mbedtls_md_get_handle( ctx );
     if( md_info == MBEDTLS_MD_INVALID_HANDLE )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
@@ -648,9 +663,14 @@ int mbedtls_md_hmac_reset( mbedtls_md_context_t *ctx )
 
     mbedtls_md_handle_t md_info;
 
-    if( ctx == NULL || ctx->hmac_ctx == NULL )
+    if( ctx == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
+#if !defined(MBEDTLS_MD_SINGLE_HASH)
+    if( ctx->hmac_ctx == NULL )
+        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
+#endif /* !MBEDTLS_MD_SINGLE_HASH */
+
     md_info = mbedtls_md_get_handle( ctx );
     if( md_info == MBEDTLS_MD_INVALID_HANDLE )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );