Pregnancy rates after vasectomy reversal vary among different reporting surgeons. To study those patients who are most likely to achieve pregnancy after vasectomy reversal, and to eliminate the effect of variations in surgical technique and operative findings on surgical outcome, the pregnancy rate after vasectomy reversal was calculated in men who achieved completely and consistently normal postoperative semen analyses (sperm concentration 20 x 10(6)/ml. or more and sperm motility 50% or greater). Of 95 patients who met the study criteria 58 (61.1%) achieved pregnancy and 37 (30.9%) did not. Including an allowance for some patients who will achieve pregnancy beyond the study-followup, it is concluded that the maximum pregnancy probability for vasectomy reversal is approximately 67%. Failure to achieve pregnancy in approximately a third of the patients may be explained by partner infertility, epididymal dysfunction and sperm antibodies. Studies that report pregnancy chances in excess of two-thirds must have different patient demographics and/or different methods of statistical analysis.