The most important cause of mortality and morbidity of COVID-19 is lung involvement. In this study, the effects of pulmonary rehabilitation (PR) in the post-acute COVID-19 period on lung functions, functional capacity, dyspnea, quality of life, and psychiatric state were investigated. Patients were admitted to a PR program after discharge when their general condition had stabilized. The patients' scores of forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC ratio, maximum vital capacity (VCmax), peripheral arterial oxygen saturation (PaO2), 6-minute walking distance (6MWD), Medical Research Council Dyspnea Scale (MRC), St. George Respiratory Questionnaire (SGSA), and Hospital Anxiety and Depression Scale (HADS) before and after pulmonary rehabilitation were compared. The patients were divided into three groups, mild, moderate, and severe, according to their thorax CT findings. A total of 52 patients [mean age: 46.7 ± 12.5 (range: 19-76) years] were included in the study. Nineteen patients were in the mild group, 16 in the moderate group, and 17 patients comprised the severe group. Comparing the parameters before and after PR, significant improvement was observed in all three groups in the evaluation parameters after treatment including FVC, FEV1, FEV1/FVC, 6MWD, and MRSC; SGSA symptoms, activity, effects and total scores; HADS depression, anxiety, and total scores (p<0.05 for all). PR is a beneficial treatment for patients with COVID-19 with lung involvement for improving lung functions, eliminating dyspnea, and improving functional capacity, psychological status, and life quality of the patient.