The clinico-epidemiological pattern of malarial infection in a cohort of pregnant women and infants was analysed during a malaria epidemic (1997-1998). The subjects were all members of tribal communities in an isolated and almost inaccessible area of central India. Overall, 151 (55%) of the 274 pregnant women investigated were found to have malarial infections at some time during the study, with Plasmodium falciparum predominating (88% of infections). All of the women investigated, whether primigravidae (42% found infected), secundigravidae (68%) or multigravidae (54%), were at great risk of developing severe malaria. When trimesters were compared, the highest prevalence of P. falciparum infection was recorded in the second (59% infected), irrespective of parity. Of the women found infected with P. falciparum, 3% had abortions, 4% stillbirths and 2% had babies who died while neonates. The small number of P. vivax infections observed prevented similar analyses for this species of parasite. Malarial infection was also seen in 218 (41%) of the 535 infants investigated. The values of age-specific prevalences revealed that > 30% of the infants examined at 2 months of age were then found to have P. vivax and/or P. falciparum parasitaemias. At 1 year of age, overall malaria prevalence was 50%, with P. vivax representing 25% of the infections and P. falciparum the rest. Subsequent follow-up revealed that three of the infants investigated, each of whom had had P. falciparum infections previously, died before their first birthdays. Re-infections (or treatment failures) were found to be common, both in the infants and the pregnant women. Pregnant women and infants from the study area clearly require systematic intervention to reduce their malaria-attributable morbidity.