Background Determination of the human immunodeficiency virus (HIV) exposure status in infants and young children is required to guarantee timely diagnosis and access to appropriate care. HIV prevalence among Mozambican women aged 15-49 years is 15%, and vertical transmission rate is still high. The study investigated HIV exposure in children aged less than 2 years in Mozambique and the factors associated with unknown HIV exposure and with HIV exposure status in this population. Methods This was a cross-sectional analytical study using data from the 2015 Survey of Indicators on Immunization, Malaria and HIV/AIDS in Mozambique. A total of 2141 mothers (15-49 years) with children aged less than 2 years were interviewed. The dependent variables were "known HIV exposure status in a child" and "HIV-exposed child," and the explanatory variables were mother's social, demographic, economic, and reproductive health characteristics. We used binary and logistic regression, adjusted for complex sampling, to determine the association between variables. Results HIV exposure status was unknown in 27% of children (95% CI, 25.1-28.9). Mothers residing in the North (AOR, 4.41; 95% CI, 2.18-8.91), in rural area (AOR, 2.44; 95% CI, 1.33-4.35), with no education (AOR, 2.72; 95% CI, 1.38-5.36), and not having utilized any health services in the last pregnancy (AOR, 1.9; 95% CI, 1.42-2.55) were more likely to have a child with unknown HIV exposure status. Six percent of children were HIV-exposed (95% CI, 5-7). Children were less likely to be HIV-exposed if the head of the household was a male (AOR, 0.26; 95% CI, 0.08-0.86), if the mother was residing in the North (AOR, 0.41; 95%