Qualitative studies and polling data from sub-Saharan Africa indicate that many individuals may mistakenly believe that male circumcision directly protects women from contracting HIV. This study examines whether individuals who learn that male circumcision reduces female-to-male HIV transmission also erroneously infer a reduction in direct male-to-female transmission risk (i.e. from an HIV-positive man to an uninfected woman). We used data on Malawian men (n = 917) randomized to receive information about voluntary medical male circumcision (VMMC) and HIV risk in 2008 and a random sample of their wives (n = 418). We found that 72 % of men and 82 % of women who believed that male circumcision reduces HIV risk for men also believed that it reduces HIV risk for women. Regression analyses indicated that men randomly assigned to receive information about the protective benefits of circumcision were more likely to adopt the erroneous beliefs, and that the underlying mechanism was the formation of the belief that male circumcision reduces HIV risk for men. The results suggest the need for VMMC campaigns to make explicit that male circumcision does not directly protect women from HIV-infection.