The effectiveness of various vasectomy techniques is reviewed, with a focus on methods used for vas occlusion. Spontaneous recanalization of the vas is more common than generally recognized and is often transient. Simple ligation and excision has an unacceptably high risk for failure. Techniques that include cautery seem to have a lower risk for failure than techniques that do not include cautery. There is insufficient evidence to recommend a particular standardized cautery technique, but adding fascial interposition to cautery seems to be associated with the lowest risk for failure.