The impact of HIV/AIDS on fertility in sub-Saharan Africa has received attention recently, since changes in population structure can impact on future economic development. We analyze the effect of AIDS on actual and desired fertility in rural Malawi, using data from Malawi 2004 Demographic and Health Survey and population censuses. Since AIDS was the dominating cause of death during the 1990s and early 2000s, we use prime-age adult mortality as the key explanatory variable. The focus is on heterogeneity in the response of gender-specific mortality rates. By estimating ordered probit models we show that actual fertility responds positively to male mortality but negatively to female mortality, and that the overall fertility response is positive but small. One interpretation of the findings is that the effects of female and male mortality differ because of an old-age security motive for having children. When a woman risks death before her children grow up, she is less likely to need support of children and demand should be low, but when the risk of husband’s death is high, the woman should expect to rely more on children’s support.