Index: uspace/lib/c/include/stdio.h
===================================================================
--- uspace/lib/c/include/stdio.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
+++ uspace/lib/c/include/stdio.h	(revision bd768718dfae4f0bf4db7bf22af81211b1851ee1)
@@ -57,12 +57,4 @@
 /** Default size for stream I/O buffers */
 #define BUFSIZ  4096
-
-#define DEBUG(fmt, ...) \
-	{ \
-		char _buf[256]; \
-		int _n = snprintf(_buf, sizeof(_buf), fmt, ##__VA_ARGS__); \
-		if (_n > 0) \
-			(void) __SYSCALL3(SYS_KIO, KIO_WRITE, (sysarg_t) _buf, str_size(_buf)); \
-	}
 
 enum _buffer_type {
Index: uspace/lib/posix/include/posix/stdio.h
===================================================================
--- uspace/lib/posix/include/posix/stdio.h	(revision 09d13c8e567316acfec91989df4a5d961f8fb644)
+++ uspace/lib/posix/include/posix/stdio.h	(revision bd768718dfae4f0bf4db7bf22af81211b1851ee1)
@@ -39,9 +39,4 @@
 #ifndef __POSIX_DEF__
 #define __POSIX_DEF__(x) x
-/* DEBUG macro does not belong to POSIX stdio.h. Its unconditional
- * definition in the native stdio.h causes unexpected behaviour of
- * applications which uses their own DEBUG macro (e.g. debugging
- * output is printed even if not desirable). */
-#undef DEBUG
 #endif