Gay and bisexual men experience numerous health disparities relative to heterosexual men, including high rates of HIV and suicidal behavior. Systematic community health assessments could provide direct comparisons of the burden of mortality across diseases and thus facilitate the prioritization of public health activities; however, such assessments have been precluded by the absence of sexual orientation information in vital statistics records. In this context, we used population attributable fraction to derive and compare indirect estimates of mortality for both HIV and suicide. Assuming that 2% of Canadian men are gay or bisexual, and that these men are 42 times more likely to die from HIV and 4 times more likely to die from suicide, we estimated that in 2011, suicide resulted in 46 deaths per 100,000 gay and bisexual men, while HIV resulted in 30 deaths per 100,000. Based on these estimates, suicide surpassed HIV as a leading cause of premature mortality for gay and bisexual men in 2007. Despite the large burden of suicide among gay and bisexual men, research attending to the issue in biomedical, psychology, and social science literatures is sparse, with at least ten times fewer citations than for HIV between 2003 and 2012. We urge researchers, practitioners, and community leaders to broaden the scope of gay and bisexual men’s public health priorities to include suicide and other high burden health inequities.