Anthropometric measurements were taken on 281 toddlers (24-48 mo old) in Linguère, Sénégal, to determine the prevalence of undernutrition. Blood samples collected from 271 of the toddlers were analyzed for retinol and carotenoids by HPLC. According to the National Center for Health Statistics reference values 30.2% of the population was undernourished. Serum retinol values were below the lower limit of the normal range in 71.5% of the children; 7.4% of this group had concentrations < 0.35 mumol/L, placing them at risk for xerophthalmia. Only 3% of the population had serum retinol values > or = 1.0 mumol/L. Serum carotenoids were low (< 0.70 mumol/L) in 55% of the children. Retinol-binding protein values were low and measurable concentrations of retinyl palmitate were detectable in only 17% of the children. Undernutrition and poor vitamin A status were found to exist at a concentration that would endanger health.