Maldives is a middle income country with a very low HIV prevalence. While the government has done a good job of raising awareness about AIDS in general, the level of appropriate HIV/AIDS related knowledge is low. The 2009 Demographic and Health Survey (DHS), which is a nationally representative survey of 7131 women, reported that while 97% of women had heard of AIDS, only 42% had a comprehensive knowledge about the disease. The level of HIV-related knowledge is a key factor in the spread of AIDS; we used the 2009 Maldives DHS to understand its determinants in women aged 15–49. Responses to questions assessing correct knowledge about modes of transmission (during pregnancy, delivery, breastfeeding, sexual intercourse, single partner, condom use, mosquito bites, and sharing food) were used to create a score, which was dichotomized by a median split to create a binary ‘knowledge’ (poor/good) variable. Poor/good knowledge was modelled as a function of socio-demographic (age, region, educational status, wealth, employment, and number of children), media (media exposure, internet use) and health/health system factors (use of family planning (FP), FP worker visit, health facility visit). On unadjusted analysis, older age, living in Male, being employed, number of children, media exposure, use of FP, and health facility visit were associated with having good knowledge of transmission modes. In the multivariate logistic regression, age (OR = 1.04), higher educational level (OR = 1.51), greater media exposure (OR = 1.09), having a smaller number of children (OR = 0.94), being employed (OR = 1.12), FP use (OR = 1.56) and health facility visit (OR = 1.39) were statistically significant predictors of good knowledge of transmission modes. Our analysis indicates that while there are no regional or wealth related differences in level of knowledge about HIV transmission, the media and health facility visits can be used as vehicles to improve the knowledge level about HIV transmission in adult Maldivian women.