ANDY'S ANSWER: If you are talking about intercourse, the answer is no. There is no birth control method that is 100% guaranteed that you won't get pregnant. However, using 2 different kinds of birth control at the same time (such as a condom and the pill for example) will cut your chances of getting pregnant down considerably.
On the other hand, if you don't use any birth control at all, or if you are using withdrawal (pulling out penis before ejaculation), the chances are extremely high that you WILL get pregnant.