A case-control study to investigate determinants of preterm delivery and intrauterine growth retardation (IUGR) in Bobo-Dioulasso, Burkina Faso, was conducted between December 1991 and November 1992. A total of 581 cases were recruited, 281 preterm infants with birthweight < 2500 g and 300 term infants with birthweight < 2500 g. 578 infants born at term with birthweights of 2500 g or more were recruited as controls. Logistic regression analyses identified three factors linked independently to both preterm delivery and IUGR: maternal illness during the pregnancy, nulliparity and failure to attend three antenatal consultations. In addition, primiparity and a maternal weight < 50 kg were associated with an increased risk of preterm delivery. Other factors associated with increased risk of IUGR were maternal height less than or equal to 155 cm, mid-upper arm circumference < 24 cm, and female sex of the infant. Improvements in the pre-pregnancy weight of women and in antenatal care focused on nulli- and primiparous women might in this population, reduce substantially the incidence of preterm delivery and IUGR.