The purpose of this paper is to analyse the impact of HIV/AIDS on fertility in Malawi. The future course of fertility will have an impact on both macroeconomic variables, such as GDP per capita, and various socioeconomic factors like mother-to-child-transmission of HIV, child mortality, the number of orphans, and public expenditures on schooling. Data on both prime-age adult mortality and HIV prevalence rates at districts level are used to measure the impact of HIV/AIDS, exploiting the large geographical variation in the distribution of HIV/AIDS in Malawi. Fertility is estimated for individual women, and measured as the number of births given during the last five years. Estimations are also carried out for the desired number of children. The major finding is that HIV/AIDS reduces fertility. Uninfected women both give birth to and desire to have fewer children in districts where prime-age adult mortality and HIV-prevalence are high, and vice versa. However, for young women, aged 15-19, there is a positive relationship between fertility and prime-age adult mortality and HIV prevalence, possibly because they wish to have children while being uninfected. This is likely to have negative effects on both educational attainment and child mortality. As also shown by previous studies, HIV-infected women give birth to fewer children than uninfected women. This is probably due to changed fertility preferences, as well as to physiological factors.