diff --git a/internal/bundler/bundler.go b/internal/bundler/bundler.go
index 75ed823d3d0..17a3c705ad8 100644
--- a/internal/bundler/bundler.go
+++ b/internal/bundler/bundler.go
@@ -196,7 +196,7 @@ func parseFile(args parseArgs) {
 			mimeType = http.DetectContentType([]byte(source.Contents))
 		}
 		encoded := base64.StdEncoding.EncodeToString([]byte(source.Contents))
-		url := "data:" + mimeType + ";base64," + encoded
+		url := "data:" + strings.ReplaceAll(mimeType, "; ", ";") + ";base64," + encoded
 		expr := ast.Expr{Data: &ast.EString{Value: lexer.StringToUTF16(url)}}
 		result.file.ast = parser.LazyExportAST(args.log, source, args.options, expr, "")
 		result.file.ignoreIfUnused = true
diff --git a/internal/bundler/bundler_loader_test.go b/internal/bundler/bundler_loader_test.go
index 52f6c9190e6..62bac276ac1 100644
--- a/internal/bundler/bundler_loader_test.go
+++ b/internal/bundler/bundler_loader_test.go
@@ -401,11 +401,11 @@ func TestLoaderDataURLCommonJSAndES6(t *testing.T) {
 		expected: map[string]string{
 			"/out.js": `// /x.txt
 var require_x = __commonJS((exports, module) => {
-  module.exports = "data:text/plain; charset=utf-8;base64,eA==";
+  module.exports = "data:text/plain;charset=utf-8;base64,eA==";
 });
 
 // /y.txt
-var y_default = "data:text/plain; charset=utf-8;base64,eQ==";
+var y_default = "data:text/plain;charset=utf-8;base64,eQ==";
 
 // /entry.js
 const x_url = require_x();