Posted by a reviewer on Amazon

There is a silicone seal in the lid

Posted by a reviewer on Amazon

They are still wonderful the lids are actually to me harder to store than they were before

Posted by a reviewer on Amazon

The rigid plastic bottom is sealed with a tabbed lid that has a gasket

Posted by a reviewer on Amazon

This container is nice and sturdy for when you need something other than those flimsy cheap ones

Posted by a reviewer on Amazon

I admit thats a tough test for a container even one that should be leak proof

Posted by a reviewer on Amazon

After about a half hour there was a very small amount of leakage into the grooves of the lid but not very much at all

Posted by a reviewer on Amazon

So while i wouldnt call it leak proof it comes pretty dang close

Posted by a reviewer on Amazon

If it had just reminded me to loosen the lid before microwaving that would be great but to remove it entirely decreases the usefulness of the container