The influence of the alpha-thalassaemia gene on the haematological, biochemical and clinical presentation of sickle cell anaemia (SCA) was investigated in Saudi patients with 1 or 2 alpha-gene deletions. The results were compared to the results obtained in SCA patients without alpha-thalassaemia. In SCA patients with 2 gene deletions (homozygous alpha-thalassaemia 2), the mean cell volume, mean cell haemoglobin and Hb F were significantly lower (p less than 0.05), while packed cell volume and Hb A2 level were considerably higher (p less than 0.05) than in the SCA patients without alpha-thalassaemia. RBC and haemoglobin were higher in the former group, but the difference was not statistically significant. Patients with 1 gene deletion had intermediate values. Among the biochemical parameters, the bilirubin level was highest in patients with 1 gene deletion. Triglyceride, cholesterol, creatinine and urea levels were lower in all SCA patients, while alkaline phosphatase (ALP) and transaminases were elevated. The increase in the levels of ALP, SGOT and SGPT was maximum in the SCA patients with 2 gene deletions, but except for SGOT, the increase was not statistically significant. The retrospective analysis of the clinical data revealed that SCA patients with alpha-thalassaemia had fewer complications and had received fewer blood transfusions than the patients without alpha-thalassaemia.