diff --git a/types/opossum/index.d.ts b/types/opossum/index.d.ts
index f1e14a939b..b955f940e3 100644
--- a/types/opossum/index.d.ts
+++ b/types/opossum/index.d.ts
@@ -1,6 +1,7 @@
-// Type definitions for opossum 1.8
-// Project: https://github.com/bucharest-gold/opossum
+// Type definitions for opossum 1.9
+// Project: https://github.com/nodeshift/opossum
 // Definitions by: Quinn Langille <https://github.com/quinnlangille>
+//                 Lance Ball <https://github.com/lance>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.8
 
@@ -31,6 +32,7 @@ export class CircuitBreaker {
     static readonly hystrixStats: symbol;
     static readonly enabled: symbol;
     static readonly warmUp: symbol;
+    static readonly volumeThreshold: symbol;
 }
 
 export interface CircuitBreakerOptions {
@@ -45,6 +47,7 @@ export interface CircuitBreakerOptions {
     errorThresholdPercentage?: number;
     enabled?: boolean;
     allowWarmUp?: boolean;
+    volumeThreshold?: number;
 }
 
 export default function circuitBreaker(
diff --git a/types/opossum/opossum-tests.ts b/types/opossum/opossum-tests.ts
index 3f020eff52..9ec5425416 100644
--- a/types/opossum/opossum-tests.ts
+++ b/types/opossum/opossum-tests.ts
@@ -17,7 +17,8 @@ const options: CircuitBreakerOptions = {
     capacity: 1,
     errorThresholdPercentage: 1,
     enabled: true,
-    allowWarmUp: true
+    allowWarmUp: true,
+    volumeThreshold: 1
 };
 
 const testWithOptions: CircuitBreaker = circuitBreaker(_blank, options);
@@ -44,3 +45,4 @@ const shouldBeSymbol7: symbol = CircuitBreaker.hystrixStats;
 const shouldBeSymbol8: symbol = CircuitBreaker.status;
 const shouldBeSymbol9: symbol = CircuitBreaker.enabled;
 const shouldBeSymbol10: symbol = CircuitBreaker.warmUp;
+const shouldBeSymbol11: symbol = CircuitBreaker.volumeThreshold;