||Background: Transplant recipients have elevated cancer risk, due in part to immunosuppression and infection with oncogenic viruses. Prior studies have been limited to kidney recipients or too small to adequately characterize cancer risk.Methods: The Transplant Cancer Match (TCM) Study links the U.S. Scientific Registry of Transplant Recipients with 13 state and regional cancer registries. We calculated standardized incidence ratios (SIRs) comparing observed cancers in transplant recipients with the number expected, based on sex-, age-, race-, year-, and region-specific population rates. For selected cancers, we evaluated SIRs according to transplanted organ and time since transplant.Results: Linkage with cancer registries yielded data on 175,822 transplant recipients (38% of the U.S. total 1987-2010). The most common transplanted organs were kidney (58%), liver (22%), heart (10%), and lung (4%). Malignancies for which risk was elevated (p<0.001) included non-Hodgkin lymphoma (NHL, SIR=7.5, N=1496); cancers of the lip (SIR=16.6, N=130), anus (SIR=5.8, N=90), liver (SIR=11.2,N=945), lung (SIR=1.9, N=1396), thyroid (SIR=2.9, N=238), and kidney (SIR=4.6, N=761); melanoma (SIR=2.4, N=379); Hodgkin lymphoma (SIR=3.6, N=85); and Kaposi sarcoma (SIR=60.5, N=120). NHL showed bimodal onset, with highest risk in the fi rst year and 10 years post-transplant. Kidney cancer risk was high in kidney/pancreas recipients (SIR=6.5) and also showed a bimodal onset pattern. Of note, kidney cancer risk was also increased in liver and thoracic organ recipients (SIRs 1.8 and 2.7), with elevated risk manifesting after 5 years. In contrast, elevated liver cancer risk was limited to liver recipients, who manifested exceptional risk in the first 3 months (SIR=929) and continuing risk out to 10 years (SIRs 1.1-4.3).Comment: Transplant recipients have increased risk for diverse cancers, particularly virus-related cancers and lymphomas. Early kidney cancers in kidney recipients may be due to residual effects of end-stage renal disease, but late cases among all recipients could be caused by chronic medication toxicity or immunosuppression. In liver recipients, very early liver cancers represent prevalent cases in the recipient liver, while persistent risk may reflect hepatitis virus infection. The TCM Study's large size and representative coverage of the U.S. transplant population are strengths for further research.