diff --git a/src/shared/transitions.js b/src/shared/transitions.js
index 6d573f68fd..bef36e741a 100644
--- a/src/shared/transitions.js
+++ b/src/shared/transitions.js
@@ -106,7 +106,7 @@ export function wrapTransition(component, node, fn, params, intro, outgroup) {
 						// when introing, discard old animations if there are any
 						return anim && (program.delta < 0 || !/__svelte/.test(anim));
 					})
-					.concat(program.name + ' ' + duration + 'ms linear 1 forwards')
+					.concat(program.name + ' ' + program.duration + 'ms linear 1 forwards')
 					.join(', ');
 			}
 
diff --git a/test/runtime/samples/transition-css-duration/_config.js b/test/runtime/samples/transition-css-duration/_config.js
new file mode 100644
index 0000000000..8a4f88431c
--- /dev/null
+++ b/test/runtime/samples/transition-css-duration/_config.js
@@ -0,0 +1,11 @@
+export default {
+	test(assert, component, target, window, raf) {
+		component.set({ visible: true });
+		const div = target.querySelector('div');
+
+		raf.tick(25);
+		component.set({ visible: false });
+
+		assert.ok(~div.style.animation.indexOf('25ms'));
+	},
+};
diff --git a/test/runtime/samples/transition-css-duration/main.html b/test/runtime/samples/transition-css-duration/main.html
new file mode 100644
index 0000000000..d3eb2bee78
--- /dev/null
+++ b/test/runtime/samples/transition-css-duration/main.html
@@ -0,0 +1,18 @@
+{{#if visible}}
+	<div transition:foo></div>
+{{/if}}
+
+<script>
+	export default {
+		transitions: {
+			foo() {
+				return {
+					duration: 100,
+					css: t => {
+						return `opacity: ${t}`;
+					}
+				};
+			}
+		}
+	};
+</script>
\ No newline at end of file