Recent evidence across sub-Saharan Africa shows married women face heightened risks of contracting HIV compared to the never-married. Vulnerability of married women to HIV infection is linked to a number of factors including their inability to negotiate safer sex, inter alia, asking their husbands to use condoms or refusing sexual intercourse even in high risk situations. This study examined what influences married women's ability to say they can ask their sexual partners to use condoms or refuse sexual intercourse. Demographic and Health Survey data from 2,950 married women were analyzed using complementary log-log models. Married women in Ghana were more likely to say they can ask their husbands to use condoms when they know condoms can protect against HIV transmission and had been tested for their HIV serostatus. Also, women who know sexual abstinence can protect against HIV transmission were more likely to say they can refuse sex. Wealthier and highly educated women were more likely to say they can refuse to have sex with their husbands or ask them to use condoms, compared to poorer and less educated women. It is recommended that policy makers promote specific knowledge related to HIV prevention (condom use, HIV testing), while improving the social and economic circumstances of married women in Ghana.