WOS: 000487340900025Pneumocystis jirovecii pneumonia (commonly called Pneumocystis pneumonia or PCP) is an opportunistic infection that occurs in immunocompromised individuals. 26 year-old male patient admitted to nephrology department for hypervolemic hyponatremia and consulted to our clinic due to the desaturation. He has been diagnosed with collapsing glomerulonephritis and he was using cyclosporine and prednisolone. Postero-anterior chest X-ray showed a blunt left cardiodiaphragmatic sinus. After ten days the patient's hypoxia deepened. Repeated chest X-ray showed bilateral perihilar heterogeneous opacity. Pneumocystis jirovecii was detected in lavage culture. We presented a case of Pneumocystis Jirovecii pneumonia secondary to cyclosporin toxicity because of a rare case