The object of this study was to assess the ability of pallor and other clinical signs, including those in the Integrated Management of Childhood Illness (IMCI) guidelines developed by WHO and UNICEF, to identify severe anaemia and some anaemia in developing country settings with and without malaria. A total of 1226 and 668 children aged 2 months to 5 years were prospectively sampled from patients presenting at, respectively, a district hospital in rural Uganda and a children's hospital in Dhaka, Bangladesh. The study physicians obtained a standardized history and carried out a physical examination that included pallor, signs of respiratory distress, and the remaining IMCI referral signs. The haematocrit or haemoglobin level was determined in all children with conjunctival or palmar pallor, and in a sample of the rest. Children with a blood level measurement and assessment of pallor at both sites were included in the anaemia analysis. Using the haematocrit or haemoglobin level as the reference standard, the correctness of assessments using severe and some pallor and other clinical signs in classifying severe and some anaemia was determined. While the full IMCI process would have referred most of the children in Uganda and nearly all the children in Bangladesh with severe anaemia to hospital, few would have received a diagnosis of severe anaemia. Severe palmar and conjunctival pallor, individually and together, had 10-50% sensitivity and 99% specificity for severe anaemia; the addition of grunting increased the sensitivity to 37-80% while maintaining a reasonable positive predictive value. Palmar pallor did not work as well as conjunctival pallor in Bangladesh for the detection for severe or some anaemia. Combining "conjunctival or palmar pallor" detected 71-87% of moderate anaemia and half or more of mild anaemia. About half the children with no anaemia were incorrectly classified as having "moderate or mild" anaemia. Anaemia was more easily diagnosed in Uganda in children with malaria. Our results show that simple clinical signs can correctly classify the anaemia status of most children. Grunting may serve as a useful adjunct to pallor in the diagnosis of severe anaemia. Conjunctival pallor should be added to the IMCI anaemia box, or the guidelines need to be adapted in regions where palmar pallor may not readily be detected.