Sirolimus-associated pulmonary problems are rare but life threatening. Pulmonary problems due to sirolimus treatment are interstitial pneumonitis, bronchiolitis obliterans organizing pneumonia (BOOP), and alveolar hemorrhage. We present a case of sirolimus-related cough in the absence of any pulmonary radiological findings. A 55-year-old man with a history of 4 years of hemodialysis therapy because of end-stage renal disease of unknown etiology underwent cadaveric renal transplantation in June 2006. Three days following the initiation of sirolimus therapy he complained of dry cough and fever. There were no clinical or laboratory findings compatible with specific pulmonary disease. After switching sirolimus to tacrolimus, the cough improved within 1-2 days and resolved in 5 days. Sirolimus should be considered in the differential diagnosis of pulmonary problems in the early posttransplantation period even in the absence of radiological findings.