Objectives To examine trends in vasectomy and vasovasostomy, and the surgical complications and factors associated with reversal after vasectomy, and paternity after vasovasostomy.Patients and methods Procedure rates were estimated from 1980 to 1996 in the population of Western Australia. Linked hospital morbidity records were used in the follow-up of men after vasectomy to estimate the risks of complications and reversals. Records of vasovasostomies were linked to the paternity field on birth registrations. Independent effects of the study factors were examined using Cox regression.Results There was little net change in vasectomy rates, whereas vasovasostomy rates increased in men aged 30-49 years. Risks of surgical complications were low and decreased for vasovasostomy. At 12-15 years after vasectomy, the risk of reversal levelled at 2.4% in the total cohort and at 11.1% in men aged 20-24 years. The risk of vasovasostomy was 69% greater after vasectomy performed in 1994-96 than in 1980-84 (P = 0.011). The factors strongly associated with reversal were age <30 years and being single, divorced or separated at the time of vasectomy. Paternity was achieved after an estimated 53% of vasovasostomies. Successful reversal was more likely if the man was younger at vasectomy and the time elapsed was comparatively short. Compared with vasovasostomies performed in 1980-84, the success rate of those in 1994-96 was almost four times higher.Conclusion Population rates of vasectomy are stable but the risk of seeking a reversal has increased. Outcomes after vasovasostomy have improved. Care should be taken during the counselling of men before vasectomy, and especially in those aged <30 years.