Growth and nutritional status were assessed in a probabilistic sample of public schoolchildren (1,705 girls and 1,682 boys) in the city of Rio de Janeiro in 1999. Nutritional status of the under-10-year group was assessed by z < -2 (undernutrition) for body mass for height and height for age and by z > +2 for body mass for height (overweight). For children over 10, the 5th and 85th percentiles of body mass index for age were used to assess underweight and overweight, respectively. Prevalence rates of overweight and obesity according to the International Obesity Task Force criteria were also calculated. Prevalence rates for undernutrition were below expected for the reference population. Prevalence of overweight was approximately 18% and 14% for girls and boys, respectively, and obesity was 5% for both sexes. The results of the present study are similar to findings from population-based surveys in Brazil: low prevalence of undernutrition and high prevalence of overnutrition.