This chapter discusses the aetiology, incidence, screening, diagnosis, prognosis factors, and treatment of the cancer following solid organ transplant. After infection and cardiovascular disease, malignancy is the next most common cause of death in solid organ transplant recipients. Far more commonly, cancer develops de novo in the recipient some time after transplantation, with the risk increasing progressively as a function of time after transplantation. Overall, the risk of malignancy in transplant recipients is 200‐300% that of age‐ and sex‐matched controls. This increase in risk is mostly dependent upon the organ transplanted and the associated nature, intensity and duration of the immunosuppressive regimen. The magnitude of the increase in cancer risk varies by cancer type and site. The greatest increase is observed in cancers associated with oncogenic viral infections. The prognosis for each cancer is substantially inferior for transplant recipients than for patients who are not transplant recipients.