diff --git a/xasm.1.txt b/xasm.1.txt
index 8cc2b42..4c708a9 100644
--- a/xasm.1.txt
+++ b/xasm.1.txt
@@ -275,10 +275,11 @@ Five options are available:
 - `H` - generate Atari executable headers
 - `L` - write to the listing
 - `O` - write to the object file
+- `U` - warn of unused labels
 
 +
 You can turn any of these on or off.
-The default (if no `OPT` specified) is `opt f-g-h+l+o+`.
+The default (if no `OPT` specified) is `opt f-g-h+l+o+u+`.
 Examples:
 +
 ------------------------------------------------------------------------------
diff --git a/xasm.d b/xasm.d
index 130275a..0b9932a 100644
--- a/xasm.d
+++ b/xasm.d
@@ -48,6 +48,7 @@ bool option5200; // opt g
 bool optionHeaders; // opt h
 bool optionListing; // opt l
 bool optionObject; // opt o
+bool optionUnusedLabels; // opt u
 
 string currentFilename;
 int lineNo;
@@ -2155,6 +2156,10 @@ void assemblyOpt() {
 		case 'o':
 			optionObject = readOption();
 			break;
+		case 'U':
+		case 'u':
+			optionUnusedLabels = readOption();
+			break;
 		default:
 			column--;
 			return;
@@ -2687,7 +2692,7 @@ void assemblyLine() {
 				assert(label in labelTable);
 				currentLabel = labelTable[label];
 				currentLabel.passed = true;
-				if (currentLabel.unused && getOption('u'))
+				if (currentLabel.unused && getOption('u') && optionUnusedLabels)
 					warning("Unused label");
 			}
 		}
@@ -2827,6 +2832,7 @@ void assemblyPass() {
 	optionHeaders = true;
 	optionListing = pass2;
 	optionObject = true;
+	optionUnusedLabels = true;
 	willSkip = false;
 	skipping = false;
 	repeatOffset = 0;