Most of our knowledge about maternal–fetal conflict derives from the battle over scarce nutritional resources. How do other stressors like infectious diseases alter the maternal–fetal relationship? In this article, we use the example of malaria infection during pregnancy to explore the altered maternal–fetal relationship in the presence of an infectious disease. While adults living in regions endemic to Plasmodium falciparum malaria are generally immune, pregnant women experience significantly more frequent and severe infections. These infections generally resolve within a few days of birth and rarely cross the placenta, but the infants often experience poor birth outcomes, particularly low birth weight. This article summarizes what is known about the proximate, or physiological, mechanisms by which malaria causes more severe or frequent infections for pregnant versus nonpregnant women in endemic regions and then utilizes an evolutionary approach to focus on the altered maternal–fetal relationship during malaria-infected pregnancy. Am. J. Hum. Biol. 2009. © 2009 Wiley-Liss, Inc.