In Niger, malnutrition underlies the high child mortality (319/1,000). The prevalence of acute malnutrition (weight/height below minus 2 z score) is more than 16% in the 0 to 5 year old range. The situation in the urban areas in slightly better than average (child mortality of 210.3/1,000). Thus the situation is very serious. The efficacy of intensive nutritional rehabilitation centers and ambulatory nutritional rehabilitation centers is controversial. The practices and knowledge of the staff of the ambulatory centers in Niamey was studied by weekly session meetings. The shortcomings could be explained by the absence of individual care, the additional work for the mothers, the mothers' illiteracy, the costs, the domestic problems and problems of cultural support, passivity of screening for malnutrition associated with the very low and irregular nutritional value of the meals supplied to the children. However, these centers exist, and they have staffs. The sessions were therefore used to develop and implement alternative strategies, and the role of the ambulatory units was discussed. The program was evaluated according to mothers' compliance, children's nutritional status, length of stay, rate of transfer to the hospital scored by retrospective analysis of the data for 397 children followed between July and October for each 1993, 1994 and 1995. The nutritional status on admission was similar for each of the three years (weight/height - 2.6 z score). The number of children with weight gain increased from 35 to 127 (P < 0.005). The rate of loss to follow-up decreased from 67% to 32% (P < 0.005). In 1993 the mothers were expected to attend daily. In 1995, after 5 to 10 days of training, follow-up was once weekly. The length of care decreased from 64.3 to 46.9 days for a similar weight gain (3.5 g/kg/day). Transfer to the hospital decreased from 10.7% in 1993 to 5.7% in 1995 (P < 0.0001), whereas this score remained high in the Niamey health centers without and ambulatory unit (24.7 in 1995). Thus the efficacy of these units can be improved although long-term outcome has yet to be demonstrated. It is also necessary to improve screening of malnourished children attending daily out-patients clinics.