The reference value of erythrocyte sedimentation rate (ESR) should be established for a population concerned because it is influenced by many local conditions. It has not yet been determined in healthy children of Bangladesh. This study was done to determine the reference value of ESR in Bangladeshi children. ESR was determined in a sample of 413 'healthy' primary school students (259 boys and 154 girls, mean age 8.7 years). Ninety-five percent of them had ESR < or = 30 mm (Westergren 1 h). Our findings suggest that ESR value > 30 mm (Westergren 1 h) should be considered high in Bangladeshi primary school children.