The Cali Study involved the random assignment of 301 malnourished children to be exposed to one (CT1, n = 113), two (CT2, n = 64), three (CT3, n = 62) or four (CT4, n = 62) 9-mo periods of a multifocal day care-based intervention (i.e., education, health and nutrition). The ages at which the intervention was initiated for Groups CT4, CT3, CT2 and CT1 were 3.5, 4.2, 5.2 and 6.1 y, respectively. After the experimental phase, children were followed up in elementary school until they were 10.4 y old. Our secondary data analyses show that children who were exposed at an earlier age and for a longer period of time showed the highest degree (P < or = 0.05) of improvement in weight and linear growth during the pre-school period. These improvements in physical growth could no longer be detected 3 y after the termination of the intervention.