Can married or cohabitating women in patriarchal societies, who are often disproportionately affected by STI/HIV infections, negotiate protective sex when perceived necessary by refusing sex or asking for condom use during sex? Protective sex negotiation was examined through measures of power relations related to whether or not a woman has a say in sexual activities within marriage. The study hypothesis was that women who are more able to refuse sex or ask for condom use before sexual intercourse will be more able to discuss and reach agreement with their spouses on protective sex practices when needed. The study used data from DHS surveys conducted in Cote d’Ivoire and Nigeria in 2012 and 2013 respectively. Multivariate logistic regression models were used to predict women’s ability to negotiate protective sex in Cote d’Ivoire and Nigeria. The findings show that moderately high percentages of women in both countries reported the ability to negotiate protective sex, with a higher percentage reporting the ability to refuse sex compared with the ability to ask partners to use a condom. The logistic regression results showed that, in the two countries, women’s ability to refuse sex or ask their partners to use a condom, varied by gender- and power-mediating factors, women’s characteristics and behavioural factors. The study draws attention to the need to intensify efforts to promote more-egalitarian relationships between partners through culturally appropriate interventions.