diff --git a/include/minix/portio.h b/include/minix/portio.h
index c5aa3d68f..efb8c75e4 100644
--- a/include/minix/portio.h
+++ b/include/minix/portio.h
@@ -17,12 +17,6 @@ unsigned inl(u32_t _port);
 void outb(u16_t _port, u8_t _value);
 void outw(u16_t _port, u16_t _value);
 void outl(u16_t _port, u32_t _value);
-void insb(u16_t _port, void *_buf, size_t _count);
-void insw(u16_t _port, void *_buf, size_t _count);
-void insl(u16_t _port, void *_buf, size_t _count);
-void outsb(u16_t _port, void *_buf, size_t _count);
-void outsw(u16_t _port, void *_buf, size_t _count);
-void outsl(u16_t _port, void *_buf, size_t _count);
 void intr_disable(void);
 void intr_enable(void);