diff --git a/src/os_unix.c b/src/os_unix.c
index c6d386b..66903e0 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -4160,11 +4160,6 @@
     static char	envbuf_Servername[60];
 #  endif
 # endif
-    long	colors =
-#  ifdef FEAT_GUI
-	    gui.in_use ? 256*256*256 :
-#  endif
-	    t_colors;
 
 # ifdef HAVE_SETENV
     setenv("TERM", term, 1);
@@ -4174,7 +4169,7 @@
     setenv("LINES", (char *)envbuf, 1);
     sprintf((char *)envbuf, "%ld", columns);
     setenv("COLUMNS", (char *)envbuf, 1);
-    sprintf((char *)envbuf, "%ld", colors);
+    sprintf((char *)envbuf, "%d", t_colors);
     setenv("COLORS", (char *)envbuf, 1);
 #  ifdef FEAT_TERMINAL
     if (is_terminal)
diff --git a/src/term.c b/src/term.c
index ef91b8f..f5d5dbc 100644
--- a/src/term.c
+++ b/src/term.c
@@ -3122,15 +3122,21 @@
     }
     need_gather = TRUE;
 
-    // Set t_colors to the value of $COLORS or t_Co.
+    // Set t_colors to the value of $COLORS or t_Co.  Ignore $COLORS in the
+    // GUI.
     t_colors = atoi((char *)T_CCO);
-    env_colors = mch_getenv((char_u *)"COLORS");
-    if (env_colors != NULL && isdigit(*env_colors))
+#ifdef FEAT_GUI
+    if (!gui.in_use)
+#endif
     {
-	int colors = atoi((char *)env_colors);
+	env_colors = mch_getenv((char_u *)"COLORS");
+	if (env_colors != NULL && isdigit(*env_colors))
+	{
+	    int colors = atoi((char *)env_colors);
 
-	if (colors != t_colors)
-	    set_color_count(colors);
+	    if (colors != t_colors)
+		set_color_count(colors);
+	}
     }
 }
 
diff --git a/src/version.c b/src/version.c
index 392ac18..16145f2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    646,
+/**/
     645,
 /**/
     644,