diff --git a/lib/webcat/session.rb b/lib/webcat/session.rb
index a8a3af5e..da7909a4 100644
--- a/lib/webcat/session.rb
+++ b/lib/webcat/session.rb
@@ -80,6 +80,7 @@ class Webcat::Session
   end
   
   def within(scope)
+    raise Webcat::ElementNotFound, "scope '#{scope}' not found on page" if find(scope).empty?
     scopes.push(scope)
     yield
     scopes.pop
diff --git a/spec/session_spec.rb b/spec/session_spec.rb
index 10ace932..42a57ab0 100644
--- a/spec/session_spec.rb
+++ b/spec/session_spec.rb
@@ -482,6 +482,13 @@ shared_examples_for "session" do
           @session.body.should include('Hello world')
         end
       end
+      
+      it "should raise an error if the scope is not found on the page" do
+        running {
+          @session.within("//div[@id='doesnotexist']") do
+          end
+        }.should raise_error(Webcat::ElementNotFound)
+      end
     end
 
     context "with forms" do