diff --git a/crates/oq3_semantics/tests/from_string_tests.rs b/crates/oq3_semantics/tests/from_string_tests.rs
index f97ecfa..72d4b93 100644
--- a/crates/oq3_semantics/tests/from_string_tests.rs
+++ b/crates/oq3_semantics/tests/from_string_tests.rs
@@ -521,6 +521,78 @@ fn test_from_string_neg_spc_lit_float() {
     assert_eq!(expr, "-1.23");
 }
 
+#[test]
+fn test_from_string_hex_literal() {
+    let code = r##"
+0xFF;
+"##;
+    let (program, errors, _symbol_table) = parse_string(code);
+    assert!(errors.is_empty());
+    assert_eq!(program.len(), 1);
+    let expr = literal_value(&program[0]).unwrap();
+    assert_eq!(expr, "255");
+}
+
+#[test]
+fn test_from_string_hex_literal_capital() {
+    let code = r##"
+0XFF;
+"##;
+    let (program, errors, _symbol_table) = parse_string(code);
+    assert!(errors.is_empty());
+    assert_eq!(program.len(), 1);
+    let expr = literal_value(&program[0]).unwrap();
+    assert_eq!(expr, "255");
+}
+
+#[test]
+fn test_from_string_octal_literal() {
+    let code = r##"
+0o77;
+"##;
+    let (program, errors, _symbol_table) = parse_string(code);
+    assert!(errors.is_empty());
+    assert_eq!(program.len(), 1);
+    let expr = literal_value(&program[0]).unwrap();
+    assert_eq!(expr, "63");
+}
+
+#[test]
+fn test_from_string_octal_literal_capital() {
+    let code = r##"
+0O77;
+"##;
+    let (program, errors, _symbol_table) = parse_string(code);
+    assert!(errors.is_empty());
+    assert_eq!(program.len(), 1);
+    let expr = literal_value(&program[0]).unwrap();
+    assert_eq!(expr, "63");
+}
+
+#[test]
+fn test_from_string_binary_literal() {
+    let code = r##"
+0b11;
+"##;
+    let (program, errors, _symbol_table) = parse_string(code);
+    assert!(errors.is_empty());
+    assert_eq!(program.len(), 1);
+    let expr = literal_value(&program[0]).unwrap();
+    assert_eq!(expr, "3");
+}
+
+#[test]
+fn test_from_string_binary_literal_capital() {
+    let code = r##"
+0B11;
+"##;
+    let (program, errors, _symbol_table) = parse_string(code);
+    assert!(errors.is_empty());
+    assert_eq!(program.len(), 1);
+    let expr = literal_value(&program[0]).unwrap();
+    assert_eq!(expr, "3");
+}
+
 // PR #91
 #[test]
 fn test_from_string_bin_expr_no_spc() {
diff --git a/crates/oq3_syntax/src/ast/token_ext.rs b/crates/oq3_syntax/src/ast/token_ext.rs
index 3f62d1f..4c8ab4c 100644
--- a/crates/oq3_syntax/src/ast/token_ext.rs
+++ b/crates/oq3_syntax/src/ast/token_ext.rs
@@ -259,9 +259,9 @@ impl ast::BitString {
 impl ast::IntNumber {
     pub fn radix(&self) -> Radix {
         match self.text().get(..2).unwrap_or_default() {
-            "0b" => Radix::Binary,
-            "0o" => Radix::Octal,
-            "0x" => Radix::Hexadecimal,
+            "0b" | "0B" => Radix::Binary,
+            "0o" | "0O" => Radix::Octal,
+            "0x" | "0X" => Radix::Hexadecimal,
             _ => Radix::Decimal,
         }
     }