diff --git a/lib/index.js b/lib/index.js
index a9bd55c..0125830 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -408,7 +408,9 @@ Channel.from = (values, mapfn, thisArg) => {
 };
 
 Channel.of = (...values) => Channel.from(values);
-Channel.isChannel = arg => Object.getPrototypeOf(arg) === prototype;
+
+Channel.isChannel = arg =>
+  arg !== undefined && arg !== null && Object.getPrototypeOf(arg) === prototype;
 
 Channel.select = methodPromises =>
   Object.assign(
diff --git a/test/index.js b/test/index.js
index 05a0220..dda61a9 100644
--- a/test/index.js
+++ b/test/index.js
@@ -82,6 +82,8 @@ describe(`Channel function`, function() {
   it(`isChannel`, function() {
     assert(Channel.isChannel(Channel.of(0, 1, 2)));
     assert(!Channel.isChannel(Array.of(0, 1, 2)));
+    assert(!Channel.isChannel(undefined));
+    assert(!Channel.isChannel(null));
     assert(Channel.isChannel(Channel().readOnly()));
     assert(Channel.isChannel(Channel().writeOnly()));
   });