BACKGROUND: Malaria and schistosomiasis represent two of the most prevalent and disabling parasitic infections in developing countries. Few studies have evaluated the effect of maternal schistosomiasis and malaria in the peri-conceptional period on infant's risk of infection. METHODS: In Benin, women were followed from the preconception period until delivery. Subsequently, their children were followed from birth to 3 months of age. Pre-pregnancy malaria, malaria in pregnancy (MiP)-determined monthly using a thick blood smear-and urinary schistosomiasis-determined once before pregnancy and once at delivery using urine filtration-were the main maternal exposures. Infant's febrile infection (fever with respiratory, gastrointestinal and/or cutaneous clinical signs anytime during follow-up) was the main outcome. In a secondary analysis, we checked the relation of malaria and schistosomiasis with infant's hemoglobin (Hb) concentration. Both effects were separately assessed using logistic/mixed linear regression models. RESULTS: The prevalence of MiP was 35.7% with 10.8% occurring during the 1st trimester, and the prevalence of schistosomiasis was 21.8%. From birth to 3 months, 25.3% of infants had at least one episode of febrile infection. In multivariate analysis, MiP, particularly malaria in the 1st trimester, was significantly associated with a higher risk of infant's febrile infection (aOR = 4.99 [1.1; 22.6], p = 0.03). In secondary results, pre-pregnancy malaria and schistosomiasis were significantly associated with a lower infant's Hb concentration during the first 3 months. CONCLUSION: We evidenced the deleterious effect of maternal parasitic infections on infant's health. Our results argue in favor of the implementation of preventive strategies as early as in the peri-conception.