Vas irrigation during vasectomy, to effect immediate sterility or to shorten the interval between vasectomy and sterility, has received increasing attention in recent years. A review of the literature on vas irrigation is presented. Topics discussed include the effectiveness of various irrigants and irrigation methods, method and technical failures, and evidence of increased risks of recanalization, inflammation, tissue damage, and infection. Stored sperm and their location after vasectomy are explored. Suggested mechanisms for the action of irrigants are reviewed, and another mechanism is proposed. Variations in study results and our incomplete understanding of vas and seminal vesicle physiology during ejaculation (compounded by individual variations) require more investigation before large clinical trials are initiated.