diff --git a/include/polarssl/x509write.h b/include/polarssl/x509write.h
index d41e708..e90b582 100644
--- a/include/polarssl/x509write.h
+++ b/include/polarssl/x509write.h
@@ -414,7 +414,7 @@
                        int (*f_rng)(void *, unsigned char *, size_t),
                        void *p_rng );
 
-#if defined(POLARSSL_BASE64_C)
+#if defined(POLARSSL_PEM_C)
 /**
  * \brief           Write a built up certificate to a X509 PEM string
  *
@@ -455,7 +455,7 @@
 int x509write_csr_pem( x509write_csr *ctx, unsigned char *buf, size_t size,
                        int (*f_rng)(void *, unsigned char *, size_t),
                        void *p_rng );
-#endif /* POLARSSL_BASE64_C */
+#endif /* POLARSSL_PEM_C */
 
 #ifdef __cplusplus
 }