Background & objectives:Pulmonary hypertension (PHT) is a potentially life-threatening complication, detected by echocardiographic evidence of elevated tricuspid regurgitant velocity. This condition has been described in adults with sickle cell disease (SCD) and other hemolytic disorders; however, there is little information on the occurrence of this condition in pediatric & adolescent patients. This study was to screen the prevalence of pulmonary hypertension in sickle cell disease patients and to compare the exercise capacity by 6 minute walk test of included patients with normal subjects. Methods:A cross – sectional observational study of 80 patients aged 5-25 years old with sickle cell disease under steady state conditions as an outpatient. Detailed history, examination, and laboratory tests were done, also 6 minutes walk test was done. Doppler echocardiographic assessments of pulmonary-artery systolic pressure were performed for all patients who were further subdivided according to TRJV into group I (with PHT) & groupII (without PHT).Results:The prevalence of a tricuspid regurgitant jet velocity of at least 2.5 m per second was 28.75%. A high reticulocyte count, low oxygen saturation, and a high platelet count were significantly associated with elevated pulmonary artery pressures as well as higher age & longer duration of the disease. Also dyspnea, palpitation, chest pain, cardiomegaly, sleep apnea were statistically significant. There was no difference in gender, history of acute chest syndrome, hydroxyurea therapy, chronic blood transfusion, stroke, hemoglobin, and bilirubin between patients with and without elevated pulmonary artery pressures. The distance walked in 6 MWT was longer in the controls and patients without PHT than patients with PHT.Conclusions:High pulmonary artery pressures do occur in children & adults with sickle cell disease. Screening by echocardiography can lead to early detection and intervention that may potentially prevent the risk factors. Six minute walk test is a useful functional capacity test.