Thirty children with sickle cell anaemia had their serum alanine aminotransferase, alkaline phosphatase, total protein, albumin and bilirubin, assayed during vaso-occlusive crisis and at recovery. Alanine aminotransferase, alkaline phosphatase and bilirubin levels were significantly higher during crisis than at recovery, (p < 0.005) especially in the young patient. However, the total protein and albumin levels were not significantly different in crisis and at recovery. A transient hepatic functional derangement during vaso-occlusive crisis is a probable explanation for the reported changes.