BACKGROUND: Immunosuppression after kidney transplantation is associated with increased risk of malignancy, which has become the second most common cause of death among kidney transplant recipients. In this review, we report the incidence of malignancies after kidney transplantation in a single center and evaluate the incidence, characteristics, relationship to immunosuppressive drugs and discuss what clinicians must consider during a follow-up of patients after kidney transplantation. METHODS: Between May 1978 and September 2013, a total of 748 kidney transplant patients who were able to undergo a follow-up process through electronic medical records were enrolled in this retrospective cohort study to determine the potential incidence and types of malignancy that may occur after kidney transplantation and the associated impact on patients and graft survival. RESULTS: Among 748 patients, 63 cases of malignancy appeared in 54 patients (7.2%). Gastrointestinal cancer (12 cases, 19%) and post-transplant lymphoproliferative disorder (12 cases, 19%) were the two most common types of malignancy. The second most common type of malignancy was urinary tract malignancy in 10 patients. Two different types of malignancy were diagnosed in nine patients during our follow-up. The overall graft survival in malignancy patients was better, which may mean that malignancy did not affect the overall graft loss. CONCLUSIONS: Clinicians should be aware of the incidence of malignancy in transplant patients and perform routine examinations for early detection of malignancy.