BACKGROUND: Unmet need for family planning exceeds 33% in Uganda. One approach to decreasing unmet need is promoting male involvement in family planning. Male disapproval of use of family planning by their female partners and misconceptions about side effects are barriers to family planning globally and in Uganda in particular. Researchers have conducted a number of qualitative studies in recent years to examine different aspects of family planning among Ugandan men. The present study aimed to quantify men's knowledge of family planning in rural Uganda to understand how better to involve men in couples' contraceptive decision-making, particularly in low-resource settings. METHODS: Data were derived from in-person, researcher-administered surveys of men in a rural agrarian district in Uganda (N = 178). Participant demographics and knowledge of family planning methods, side effects, and use were queried. Descriptive statistics were used for analysis. RESULTS: Men were 34 years of age on average (range 18-71) and about half (56%) had a primary school education or less. Ninety-eight percent reported any knowledge of family planning, with 73% of men reporting obtaining information via radio and only 43% from health workers. The most common method known by men was the male condom (72%), but more than half also knew of injections (54%) and pills (52%). Relatively few men reported knowing about the most effective reversible contraceptive methods, intrauterine devices and implants (both 16%). Men identified many common contraceptive side-effects, such as vaginal bleeding (31%), and misconceptions about side effects, such as increased risk of infertility and birth defects, were relatively uncommon (both < 10%). About half of all men reported ever using a family planning method (53%), and 40% reported current use. CONCLUSIONS: This study's quantitative results build on those of recent qualitative studies and provide information about the types of family planning information men are lacking and avenues for getting this information to them.