Universal life insurance and whole life insurance are both considered to be permanent life insurance products. However, there are very distinct differences between the two types of life insurance.
Whole life insurance is a much safer product in that most whole life policies have a guaranteed premium which gets you a fixed death benefit and cash value that grows at fixed, guaranteed rate. However, you will pay more for whole life and you are restricted in when you cash in the cash value.
Universal life insurance is much more flexible. You can change the death benefit, the premium you pay and the interest in the cash value account grows at an amount subject to market conditions (there is usually a guaranteed minimum though). You can actually make payments if you have sufficient cash value in which to draw off.
Article courtesy of The Murray Group.