Infectious disease in transplant patients who are receiving immunosuppressive drugs is an important and potentially fatal problem. Early diagnosis and management is the key of success. Since 2006, 15 heart transplants are performed in our center. We reviewed infectious problems which occurred in three patients in early post op course and a late problem in another patient. One: 14 days after heart transplant the patient was ready for discharge. He had no problems, in the final CXR some small nodules was found. For better evaluation CT scan and then needle biopsy was done. It was found the patient had developed aspergillosis, which was managed and discharged after 10 days. This patient developed edema of scrotum 3 months after transplant, which after examination it was found to have a serious cellulitis, there was no need for surgical drainage, antibiotic therapy was done for 14 days and became better. The cause of cellulitis was a small nodule in the scrotum which was damaged by manipulation. Two: in the 4th post op. day of a heart transplant patient routine CXR showed some nodules in the CXR. Immediately CTscan and then fiber optic bronchsocopy was done with copious amount of secretions. Empiric antifungal and more potent antibiotic therapy started, the infiltrations were disappeared and the patient was discharged. Three: 1.5 years after heart transplant of a young lady, she suddenly developed severe abdominal pain and jaundice, many workups were done which was indicative of pancreatitis, but the Ig M of CMV titer was also increased. Treatment for management of CMV started, and the pancreatitis also resolved. In conclusion, in transplant patient like all immunosuppressed patients the paraclinical lad data such as CXR is more important than general condition of the patient and any small changes should be managed seriously. These patients are highly susceptible to viral, fungal and bacterial infections.