diff --git a/patterns.go b/patterns.go
index ca45aaa..2df0473 100644
--- a/patterns.go
+++ b/patterns.go
@@ -9,8 +9,8 @@ const (
 	ISBN10         string = "^(?:[0-9]{9}X|[0-9]{10})$"
 	ISBN13         string = "^(?:[0-9]{13})$"
 	UUID3          string = "^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-3[0-9a-fA-F]{3}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$"
-	UUID4          string = "^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-4[0-9a-fA-F]{3}-[89ab][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$"
-	UUID5          string = "^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-5[0-9a-fA-F]{3}-[89ab][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$"
+	UUID4          string = "^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-4[0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$"
+	UUID5          string = "^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-5[0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$"
 	UUID           string = "^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$"
 	Alpha          string = "^[a-zA-Z]+$"
 	Alphanumeric   string = "^[a-zA-Z0-9]+$"
diff --git a/validator_test.go b/validator_test.go
index 8731d76..514e627 100644
--- a/validator_test.go
+++ b/validator_test.go
@@ -1265,6 +1265,8 @@ func TestIsUUID(t *testing.T) {
 		{"987fbc9-4bed-3078-cf07a-9141ba07c9f3", false},
 		{"aaaaaaaa-1111-1111-aaag-111111111111", false},
 		{"a987fbc9-4bed-3078-cf07-9141ba07c9f3", true},
+		{"A987FBC9-4BED-3078-CF07-9141BA07C9F3", true},
+		{"a987fBc9-4bEd-3078-Cf07-9141bA07c9f3", true},
 	}
 	for _, test := range tests {
 		actual := IsUUID(test.param)
@@ -1283,6 +1285,8 @@ func TestIsUUID(t *testing.T) {
 		{"xxxa987fbc9-4bed-3078-cf07-9141ba07c9f3", false},
 		{"a987fbc9-4bed-4078-8f07-9141ba07c9f3", false},
 		{"a987fbc9-4bed-3078-cf07-9141ba07c9f3", true},
+		{"A987FBC9-4BED-3078-CF07-9141BA07C9F3", true},
+		{"a987fBc9-4bEd-3078-Cf07-9141bA07c9f3", true},
 	}
 	for _, test := range tests {
 		actual := IsUUIDv3(test.param)
@@ -1302,6 +1306,8 @@ func TestIsUUID(t *testing.T) {
 		{"934859", false},
 		{"57b73598-8764-4ad0-a76a-679bb6640eb1", true},
 		{"625e63f3-58f5-40b7-83a1-a72ad31acffb", true},
+		{"625E63F3-58F5-40B7-83A1-A72AD31ACFFB", true},
+		{"625E63f3-58F5-40b7-83A1-a72Ad31AcFfB", true},
 	}
 	for _, test := range tests {
 		actual := IsUUIDv4(test.param)
@@ -1322,6 +1328,8 @@ func TestIsUUID(t *testing.T) {
 		{"a987fbc9-4bed-3078-cf07-9141ba07c9f3", false},
 		{"987fbc97-4bed-5078-af07-9141ba07c9f3", true},
 		{"987fbc97-4bed-5078-9f07-9141ba07c9f3", true},
+		{"987FBC97-4BED-5078-9F07-9141BA07C9F3", true},
+		{"987FbC97-4bEd-5078-9f07-9141bA07c9f3", true},
 	}
 	for _, test := range tests {
 		actual := IsUUIDv5(test.param)