Data on malaria in pregnancy in unstable transmission areas are scarce. We investigated malaria in pregnancy at Byumba District Hospital, Rwanda, over 3 years (January 1997-December 1999). Byumba, at an altitude of 2300 m, has low levels of malaria transmission. A malaria epidemic in February 1998 led to a fourfold increase in malaria admissions among pregnant women and to a fivefold increase in maternal deaths because of malaria. Safe Motherhood programmes should note that even in non-epidemic years malaria can cause a large proportion of maternal deaths, and that national and international responses to malaria in pregnancy need strengthening.