This study was conducted on twenty patients with chronic renal failure and ten normal subjects as a control group, of comparable sex and age. For the included subjects, full history taking, full clinical examination, laboratory tests including blood levels of urea, serum creatinine, ionized serum calcium, phosphorus albumin and haemoglobin percent; chest X-ray, phrenic nerve conduction studies and pulmonary function tests pre and post-bronchodilators were done.It was found that there was elevated levels for blood urea, serum creatinine, ionized serum calcium, and phosphorus and decreased values for serum albumin and haemoglobin percent in the chronic renal failure patients compared with the control group.In patients group, revealed the presence of mild to moderate restrictive and mild major airways obstructive ventilatory dysfunction with moderate to severe small airway obstruction with statistically insignificant response to bronchodilators.Phrenic nerve parameters revealed prolongation of the conduction time in the patients group compared to the control group.The left phrenic nerve amplitude was found to be sensitive to changes in the ventilatory function as there was significant negative correlation between it and FEV1% and FEF50%.The right phrenic distal latency showed significant negative correlation with FEV1%, FEV1/FVC and FEF25-75%.From this study, we can conclude that FEV1% is sensitive to affection of phrenic nerve in patients with chronic renal failure and affection of the phrenic nerve could be a factor in derangements of pulmonary functions encountered in chronic renal failure patients.