Sixty-one children diagnosed as having non-organic failure to thrive during infancy were reviewed at an average of 5 years after their initial presentation, and were compared to a control group matched for age, sex, social class, and ethnic affiliation. Children with a previous history of failure to thrive were found to be shorter and, in particular, to gain less weight. Birthweight percentile and maternal height of children with failure to thrive were lower than those of matched children from the control group. They also had more learning difficulties and evidenced developmental delay. The degree of growth retardation and the duration of follow-up had no significant effect on the outcome. In contrast, birthweight, maternal height, and social status and, to a lesser extent, paternal parameters were good predictors of catching-up capabilities of these infants in terms of weight and height. Children who caught up faster had better school performances and came from families of higher socioeconomic status. Failure to thrive is a multifactorial process involving biological, nutritional, and environmental factors. All these components should be considered in long-term follow-up and management.