diff --git a/src/goMain.ts b/src/goMain.ts
index 39ec4a9..16df376 100644
--- a/src/goMain.ts
+++ b/src/goMain.ts
@@ -303,6 +303,10 @@
 
 	ctx.subscriptions.push(
 		vscode.commands.registerCommand('go.debug.cursor', (args) => {
+			if (vscode.debug.activeDebugSession) {
+				vscode.window.showErrorMessage('Debug session has already been started.');
+				return;
+			}
 			const goConfig = getGoConfig();
 			testAtCursor(goConfig, 'debug', args);
 		})