Background The incidence of prostate cancer in Uganda is one of the highest recorded in Africa. Prostate cancer is the most common cancer among men in Uganda. Objective This study assessed the current knowledge, attitudes and practices of adult Ugandan men regarding prostate cancer. Subjects and Methods We conducted a descriptive cross-sectional study using interviewer administered questionnaires and focus group discussions among 545 adult men aged 18–71 years, residing in Kampala, the capital of Uganda. Quantitative data were analyzed with SPSS version 20. Qualitative data were collected using audio recorded focus group discussions, transcribed and analyzed by clustering into themes. Results The majority of the respondents (324, 59.4%) were aged 18–28 years, 295 (54.1%) had heard about prostate cancer and 250 (45.9%) had never heard about it. The commonest source of information about prostate cancer was the mass media. Only 12.5% of the respondents obtained information about prostate cancer from a health worker, 37.4% did not know the age group that prostate cancer affects and 50.2% could not identify any risk factor for prostate cancer. Participants in the focus group discussions confused prostate cancer with gonorrhea and had various misconceptions about the causes of prostate cancer. Only 10.3% of the respondents had good knowledge of the symptoms of prostate cancer and only 9% knew about serum prostate specific antigen (PSA) testing. Although 63.5% thought they were susceptible to prostate cancer, only 22.9% considered getting and only 3.5% had ever undergone a serum PSA test. Conclusion There was generally poor knowledge and several misconceptions regarding prostate cancer and screening in the study population. Community based health education programs about prostate cancer are greatly needed for this population.