The effects of sickle cell disease (SCD) on right ventricular (RV) and pulmonary function in SCD patients with pulmonary hypertension is not well-known. The aim of this study was to investigate RV and pulmonary functions in patients suffering from SCD with or without pulmonary hypertension using color tissue Doppler imaging and spirometry. We evaluated 48 asymptomatic patients with SCD. All patients underwent echocardiography with tissue Doppler imaging and pulmonary function test. Patients were divided into two groups: Group 1 consisted of 27 patients (age, 18.1 ± 7.1 years) with normal pulmonary artery pressure, and group 2 consisted of 21 patients (age, 21.4 ± 7.4 years) with pulmonary hypertension. Both groups were compared with a sex- and age-matched control group including 24 normal healthy subjects (age, 19.8 ± 9.2 years). Tricuspid lateral annular systolic (Sm) and early diastolic velocity (Em) were higher in group 1 than group 2 and the control group (p < 0.05). Tricuspid lateral annular late diastolic velocities (Am), isovolumetric contraction time, and myocardial performance index (MPI) were higher and the Em/Am ratio was lower in group 2 than group 1 and the control group (p < 0.05). However, no differences were found in the tricuspid lateral annular Em deceleration time, ejection time, and isovolumetric relaxation time between group 1, group 2, and the control group. Tricuspid lateral annular Sm and Em were similar in group 2 and the control group. Forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and the diffusion capacity of the lung for carbon monoxide were decreased in both groups of patients compared to the control group (p < 0.05). However, there was no difference in respiratory rate, FEV1/FVC ratio, peak expiratory flow, and total lung capacity between group 1, group 2, and the control group. There were no differences in any indices of lung function between the two groups of patients. MPI is useful index to evaluate RV function in patients with SCD. RV diastolic function was disturbed in only SCD patients with pulmonary hypertension. On the other hand, the restrictive pattern of pulmonary function abnormalities had developed in both groups of patients.