diff --git a/include/polarssl/debug.h b/include/polarssl/debug.h
index f0cc261..fdd3627 100644
--- a/include/polarssl/debug.h
+++ b/include/polarssl/debug.h
@@ -44,14 +44,20 @@
 #define SSL_DEBUG_BUF( level, text, buf, len )           \
     debug_print_buf( ssl, level, __FILE__, __LINE__, text, buf, len );
 
+#if defined(POLARSSL_BIGNUM_C)
 #define SSL_DEBUG_MPI( level, text, X )                  \
     debug_print_mpi( ssl, level, __FILE__, __LINE__, text, X );
+#endif
 
+#if defined(POLARSSL_ECP_C)
 #define SSL_DEBUG_ECP( level, text, X )                  \
     debug_print_ecp( ssl, level, __FILE__, __LINE__, text, X );
+#endif
 
+#if defined(POLARSSL_X509_PARSE_C)
 #define SSL_DEBUG_CRT( level, text, crt )                \
     debug_print_crt( ssl, level, __FILE__, __LINE__, text, crt );
+#endif
 
 #else
 
@@ -81,9 +87,11 @@
                       const char *file, int line, const char *text,
                       unsigned char *buf, size_t len );
 
+#if defined(POLARSSL_BIGNUM_C)
 void debug_print_mpi( const ssl_context *ssl, int level,
                       const char *file, int line,
                       const char *text, const mpi *X );
+#endif
 
 #if defined(POLARSSL_ECP_C)
 void debug_print_ecp( const ssl_context *ssl, int level,
@@ -91,9 +99,11 @@
                       const char *text, const ecp_point *X );
 #endif
 
+#if defined(POLARSSL_X509_PARSE_C)
 void debug_print_crt( const ssl_context *ssl, int level,
                       const char *file, int line,
                       const char *text, const x509_cert *crt );
+#endif
 
 #ifdef __cplusplus
 }