The routinely collected weight data of 2202 pre-school children who visited two under-5 clinics in Lesotho between 1978 and 1983 were used to calculate growth curves and to assess the effects of supplementary feeding. Up to the age of 5 months growth curves were above the NCHS reference. Growth started to decrease at the age of 3 months and stabilized at 11-13 months at the 10th percentile of the reference. The decrease of growth might have been due to environmental factors such as under-nutrition and disease. If this was the case, supplementary feeding might have had a positive impact on weight, but such an effect was not observed in this study. Supplementary feeding had, however, a positive effect on attendance rates and hence contributed to higher coverage of other under-5 clinic activities, such as immunization, health and nutrition education, and growth monitoring. Whether this positive effect warrants its extra cost remains open to question.