Early marriage of girls, close to age of menarche, is a widespread practice in Arab countries. Knowledge on the cumulative effect of early maternal marriage on maternal and infant health during the childbearing period is insufficient. The objectives of this study were to estimate the prevalence of early maternal marriage in Jeddah, identify its relation with other maternal risk factors, and investigate the cumulative impact of early maternal marriage on subsequent maternal health and pregnancy outcomes throughout the reproductive period. Data were collected from six randomly selected primary health care units in Jeddah City. Married women with an infant < or = 12 completed months of age were interviewed and information on sociodemographic characteristics, maternal health and previous pregnancy outcomes were collected. Early marriage of girls before the age of 16 years accounted for 26.5% of the study population and was reported by a third of mothers currently below the age of 20 years. Illiterate mothers, housewives, multiparae, smokers and those married to a relative reported the highest proportion of marriages before their sixteenth birthday. Those who married before the age of 16 were at about double the risk of developing chronic diseases and experiencing miscarriage, stillbirths and infant deaths. These results suggest that early maternal marriage still exists in our community and is intimately related to other maternal risk factors. Maternal marriage < 16 years appears to be fraught with insecurities for the mother and infant throughout the whole length of the childbearing period and not merely the first pregnancy. Thus, even if culture norms claim early marriage of girls, it should be discouraged before the age of 16 years. Moreover, it is recommended that future research on maternal and infant health considers the cumulative effect of the various risk factors during the whole reproductive period and not only a single pregnancy outcome.