diff --git a/git-am.sh b/git-am.sh
index e7f008c7ba..9317b38935 100755
--- a/git-am.sh
+++ b/git-am.sh
@@ -444,12 +444,12 @@ else
 				set x
 				first=
 			}
-			case "$arg" in
-			/*)
-				set "$@" "$arg" ;;
-			*)
-				set "$@" "$prefix$arg" ;;
-			esac
+			if is_absolute_path "$arg"
+			then
+				set "$@" "$arg"
+			else
+				set "$@" "$prefix$arg"
+			fi
 		done
 		shift
 	fi
diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index 6131670860..58d30c9388 100644
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -209,5 +209,20 @@ case $(uname -s) in
 	find () {
 		/usr/bin/find "$@"
 	}
+	is_absolute_path () {
+		case "$1" in
+		[/\\]* | [A-Za-z]:*)
+			return 0 ;;
+		esac
+		return 1
+	}
 	;;
+*)
+	is_absolute_path () {
+		case "$1" in
+		/*)
+			return 0 ;;
+		esac
+		return 1
+	}
 esac