The main clinical use of measurements of Apo Al and Apo B is to determine a patient's risk status for the development of ischemic heart disease. Apo B is generally accepted as a contributory cause of coronary artery disease, while Apo Al apparently has a protective effect. The present study reports the plasma change of Apo Al and B in sickle cell anaemic subjects. Immunochemical findings revealed that Apo Al and B levels were found to be lower in sickle cell patients as compared with normal subjects (HbAA). The atherogenicity index given by Apo B/Apo Al remained in the normal range during periods of steady state (0.64 +/- 0.28), while subjects in painful crisis had high index values (0.95 +/- 0.35). Therefore, we concluded that epidemiological studies on a large sample of patients are needed to confirm this relationship between painful crisis and risk of developing coronary artery disease.