diff --git a/main.go b/main.go
index f3c3d0c..f5da94c 100644
--- a/main.go
+++ b/main.go
@@ -131,6 +131,7 @@ func (cli *CLI) Run(_args []string) int {
 	var camel = flag.Bool("camel", false, "Substitute (upper) camel-cased expressions")
 	var upperCamel = flag.Bool("upper-camel", false, "Substitute upper-camel-cased expressions")
 	var lowerCamel = flag.Bool("lower-camel", false, "Substitute lower-camel-cased expressions")
+	var screamingSnake = flag.Bool("screaming-snake", false, "Substitute screaming-snake-cased expressions")
 	var all = flag.BoolP("all", "a", false, "Substitute (snake|kebab|camel)-cased expressions")
 	var ruby = flag.Bool("ruby", false, "Substitute Ruby module and directory expressions")
 	var rename = flag.BoolP("rename", "r", false, "Rename files with expression")
@@ -180,6 +181,9 @@ func (cli *CLI) Run(_args []string) int {
 	if *lowerCamel || *all {
 		addSub(&substitutions, rawFrom, to, strcase.ToLowerCamel)
 	}
+	if *screamingSnake {
+		addSub(&substitutions, rawFrom, to, strcase.ToScreamingSnake)
+	}
 
 	if *ruby {
 		addSub(&substitutions, rawFrom, to, ToRubyDirectory)
diff --git a/main_test.go b/main_test.go
index 7cde7d9..32b3a5b 100644
--- a/main_test.go
+++ b/main_test.go
@@ -180,15 +180,15 @@ func TestSubstitutionWithPath(t *testing.T) {
 
 func TestSubstitutionWithCaseConversion(t *testing.T) {
 	RunInTmpRepo(func() {
-		CommitFile("README.md", "GitGsub git_gsub git-gsub")
-		_, err := RunGitGsub("--camel", "--kebab", "--snake", "git-gsub", "svn-gsub")
+		CommitFile("README.md", "GitGsub git_gsub git-gsub GIT_GSUB")
+		_, err := RunGitGsub("--camel", "--kebab", "--snake", "--screaming-snake", "git-gsub", "svn-gsub")
 
 		if err != nil {
 			t.Errorf("Command failed: %s", err)
 		}
 
 		dat, _ := ioutil.ReadFile("./README.md")
-		if string(dat) != "SvnGsub svn_gsub svn-gsub" {
+		if string(dat) != "SvnGsub svn_gsub svn-gsub SVN_GSUB" {
 			t.Errorf("Failed: %s", string(dat))
 		}
 	})