BACKGROUND: Androgens are assumed to play a central role in the pathophysiology of both prostate cancer (PC) and androgenic alopecia (AA). A correlation between the two phenotypes may be relevant for identification of men at high risk of PC. We evaluated the association between AA at different ages and PC in a large case-control study. METHODS: The case group comprised 938 PC patients recruited from a population-based cancer registry. The controls (n = 2160) were a random sample of the male general population. All subjects completed a questionnaire on risk factors for cancer, including questions on hair pattern at different ages using an adapted version of the Hamilton-Norwood scale, race and family history of PC. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multivariable logistic regression. RESULTS: Baldness at early age appeared to be associated with a lower risk of PC (baldness at age 20: OR = 0.86; 95% CI 0.69-1.07 and baldness at age 40: OR = 0.81; 95% CI 0.70-0.96). Baldness at completion of the questionnaire was not associated with PC: OR = 1.10; 95% CI 0.89-1.34. An isolated 'frontal baldness' or 'vertex baldness' pattern was not significantly associated with PC at any age. Presence of a combined 'frontal and vertex' baldness pattern at age 40 was associated with a decreased risk of PC (OR = 0.62; 95% CI 0.45-0.86). There were no significant associations between AA and aggressive PC. CONCLUSIONS: We did not find consistent positive associations between AA at different ages and PC. Surprisingly, if anything, baldness at early age is inversely related to PC in this study. Androgenic alopecia is not useful as an indicator of men at high risk of PC.