Conception among HIV-positive individuals is an important health and social issue. However, the proportion of HIV-positive women who conceive while being aware of their serostatus and the factors that influence this decision is not well documented. In a cross-sectional study, 385 HIV-positive women in the labour ward at Mulago Hospital, Uganda, were interviewed using a structured questionnaire. Data were collected on socio-demographic characteristics, contraception ever used, knowledge of antiretrovirals (ARVs), and ARVs ever used. To assess factors associated with conception among women who know their HIV-positive status, the variables were compared for women in two groups: those who conceived while knowing their HIV-positive status and those who discovered their HIV status during pregnancy. Bivariate and logistic regression analyses were used to assess confounding variables and interactions. The data show that one in every three HIV-positive women in the study population (37.1%) conceived despite being HIV-positive. Women who conceived while knowing they were HIV-positive differed from those who conceived without knowing their HIV status in regard to employment status, marital status, the employment status of their spouse/partner, and their intention to conceive. Logistic regression showed that factors independently associated with conception in this sample of HIV-positive women were: age below 25 years (odds ratio [OR] 2.06; 95% confidence interval [CI]: 1.18–3.62); unemployment (OR 2.7; 95% CI: 1.42–5.04); carrying a first pregnancy (OR 4.53; 95% CI: 2.02–9.94), being unaware of her partner's HIV status (OR 0.26; 95% CI: 0.15–0.44); having an awareness of ARVs (OR 3.66; 95% CI: 2.15–6.25); and having regrets about conceiving while being HIV-positive (OR 0.21; 95% CI: 0.09–0.46).