diff --git a/src/am_map.cpp b/src/am_map.cpp
index 28bd27aff..aac56f1c2 100644
--- a/src/am_map.cpp
+++ b/src/am_map.cpp
@@ -1695,9 +1695,9 @@ bool AM_clipMline (mline_t *ml, fline_t *fl)
 		TOP		=8
 	};
 
-	register int outcode1 = 0;
-	register int outcode2 = 0;
-	register int outside;
+	int outcode1 = 0;
+	int outcode2 = 0;
+	int outside;
 
 	fpoint_t tmp = { 0, 0 };
 	int dx;
diff --git a/src/md5.cpp b/src/md5.cpp
index 481774c7a..b81209546 100644
--- a/src/md5.cpp
+++ b/src/md5.cpp
@@ -166,7 +166,7 @@ void MD5Context::Final(BYTE digest[16])
 void
 MD5Transform(DWORD buf[4], const DWORD in[16])
 {
-	register DWORD a, b, c, d;
+	DWORD a, b, c, d;
 
 	a = buf[0];
 	b = buf[1];
diff --git a/src/p_spec.cpp b/src/p_spec.cpp
index e18f78b29..206a7e172 100644
--- a/src/p_spec.cpp
+++ b/src/p_spec.cpp
@@ -1861,7 +1861,7 @@ static void P_SpawnScrollers(void)
 
 		switch (special)
 		{
-			register int s;
+			int s;
 
 		case Scroll_Ceiling:
 		{
@@ -2393,7 +2393,7 @@ static void P_SpawnPushers ()
 {
 	int i;
 	line_t *l = lines;
-	register int s;
+	int s;
 
 	for (i = 0; i < numlines; i++, l++)
 	{