Although infections contribute to growth faltering in preschool children, malaria prevention seems to have limited impact on height status. In 2002-2003, a malaria intermittent preventive treatment (IPT) trial was conducted in Senegal, including randomly selected preschool children from 11 villages. A rapid decrease in stunting prevalence (from 28.3 to 16.3%; P < 0.0001) was reported in both intervention and placebo groups. During this 15-mo period, both groups of children benefited from active detection and prompt treatment of malaria attacks. In this study, we investigated whether management of malaria morbidity could explain the improvement of height status. An anthropometric survey, conducted in September 2004 in the area, included 929 2- to 5-y-old children. Some 539 children, previously included in the 2002-2003 IPT trial, benefited from active malaria morbidity management and formed the malaria trial group. The remaining 390 children constituted the control group. Mean height-for-age and stunting prevalence in September 2004 were compared between groups adjusting for age and mother's activity. Mean height-for-age Z-scores did not differ between trial (-1.17 +/- 0.93) and control children (-1.24 +/- 1.00; P = 0.25). Only 36- to 47-mo-old malaria trial children had a lower prevalence of stunting than controls of similar age (19.4 vs. 28.7%; P = 0.044). Compared with the usually slow progression of height status related to better living conditions, it seems very likely that the rapid improvement observed among IPT study children resulted from the trial. These findings suggest that improved health services provided by the trial may also have benefited children not included living in study villages.