Urologists are always trying to identify risk factors for prostate cancer (CaP). This population-based study is from Ontario, Canada. The study sample comprised nearly 300,000 men who underwent vasectomy and an equal number who did not. The primary outcome was incidence of prostate cancer in the groups. The secondary outcomes were: grade, stage and mortality. Median follow-up was 10.9 years. In an unadjusted data analysis, vasectomy was associated with a slightly increased risk of CaP (hazard ratio 1.13). However, after adjustment for health seeking behaviour, no association was found (hazard ratio 1.02). There was no link between vasectomy and high-grade CaP or prostate cancer-specific mortality. In summary, vasectomy does not seem to be an independent risk factor for CaP.