Abstract Background: Impaired pulmonary function in patients on hemodialysis may be caused by an underlying pulmonary disease, however the effects of hemodialysis treatment and kidney transplantation are not well understood. Aim of the work: The aim of this study was to evaluate pulmonary function among patients with chronic renal failure (CRF) undergoing hemodialysis and patients with kidney transplant. Patients and methods: This study was conducted on 60 subjects. They were classified into 3 groups: Hemodialysis group (HDG) included 20 patients with end stage renal disease (ESRD) on regular hemodialysis for at least six months and were clinically stable. Transplant group (TG) included 20 patients who had undergone kidney transplant at least six months earlier and were also clinically stable. Control group (CG) included 20 apparently healthy subjects. All subjects underwent pulmonary function testing; including resting spirometry included flow volume loop and Maximal Voluntary Ventilation (MVV), measurement of lung volumes and diffusing capacity for carbon monoxide (DLCO) using single breath technique, Six Minute Walking Test (6MWT) and arterial blood gases (ABG). Results: There was a significant difference between HDG, TG and CG regarding FVC% of predicted, FEV1% of predicted, FEF 25–75% of predicted, PEFR% of predicted and MVV% of predicted. Also there was a statistically significant difference between HDG, TG and CG regarding RV% of predicted, TLC% of predicted and RV/TLC%. Although FVC% of predicted and FEV1% of predicted were within the normal range in the 3 studied groups, there was a statistically