Comprehension is fundamental for informed consent—an individual’s right to choose a medical procedure, such as male circumcision (MC). Because optimal benefits depend on post-surgical behaviors, comprehension is particularly critical for MC programs. We evaluated clients’ comprehension of MC’s risks and benefits, wound care instructions, and risk reduction post-MC using a true/false test (n = 1181) and 92 semi-structured interviews (SSIs) in Zambia and Swaziland. Most participants (89 % Zambia, 93 % Swaziland) passed the true/false test, although adolescents scored lower (significantly so in Swaziland) than adults and one-third (including nearly half of adolescents in Zambia) said MC has no risks. SSIs indicated confusion between “risk” of adverse surgical outcomes and reduced “risk” of HIV; most respondents acknowledged the 6 week abstinence period post-MC, yet few said resuming sex early increases HIV risk. Providers should distinguish between surgical “risks” and reduced HIV “risk,” and emphasize that HIV risk increases with sex before complete healing.