OBJECTIVE--To investigate whether attacks of acute chest syndrome affected pulmonary artery pressure in patients homozygous for sickle cell disease. MAIN OUTCOME MEASURES--Pulmonary artery pressure, assessed by non-invasive echocardiographic techniques. PATIENTS--20 patients with homozygous sickle cell disease with a history of at least six episodes of acute chest syndrome and in 20 age, sex, and height matched controls with homozygous sickle cell disease without a history of acute chest syndrome. RESULTS--There was no difference in any of the echocardiographic or Doppler indices between these two groups. CONCLUSIONS--Repeated attacks of acute chest syndrome by the mean age of 12 (range eight to 16) years have not had a discernible effect upon pulmonary artery pressure.