Résumé : A randomized controlled trial was conducted in eastern Zaire to assess the effects of high dose vitamin A supplementation and regular deparasitation on the growth of 358 moderately malnourished preschool children, discharged from the hospital. The treatment groups received either vitamin A (60 mg of oily solution of retinyl palmitate, 30 mg if aged <12 mo) every 6 mo or mebendazole (500 mg) every 3 mo; the control group received no supplementation. Anthropometric data were gathered at baseline and after 6 and 12 mo of follow-up. Serum retinol concentrations were measured at baseline and after 3 mo. The three groups did not differ in sociodemographic indicators, age and sex composition, nutritional status and serum retinol concentrations at baseline. In children who were vitamin A deficient at baseline, adjusted mean weight and mid-upper arm circumference (MUAC) increments were higher in the vitamin A-supplemented group than in the control group [annual increment in weight and MUAC in vitamin A vs. control group: 2.088 vs. 1.179 kg (P = 0.029) and 2.24 vs. 0.95 cm (P = 0.012), respectively], whereas growth increment did not differ between the dewormed group and the control group. In children who were not vitamin A deficient at baseline, growth increment did not differ between the vitamin A-supplemented and control groups, whereas weight gain was lower in the dewormed group than in the control group. Vitamin A-supplemented boys gained more weight and height than control boys, whereas vitamin A-supplemented girls gained less height than control girls. Dewormed boys and girls gained less weight than control boys and girls. Programs to improve vitamin A status by high dose vitamin A supplementation may improve growth of preschool children who are vitamin A deficient, whereas deworming does not.