In 199 children with acute infections admitted to an acute general paediatric ward, the serum C reactive protein (CRP) level, using a simple latex agglutination kit, was compared with standard haematological parameters in distinguishing children with viral and bacterial infections. CRP levels proved superior to any haematological parameters singly or in combination in distinguishing these groups. A CRP level of 1:4 identified all but 13% of children with viral infections and excluded all but 15% of children with bacterial infections. The sensitivity of the test was 87%, the specificity 85%. The positive and negative predictive values were 95% and 74% respectively. Combined haematology, using total white cell count, total neutrophil count and percentage neutrophils, misclassified 26% of patients. CRP estimation could potentially help reduce unnecessary antibiotic prescription and shorten hospitalisation in febrile children. Its use in a general practice setting deserves further study.