According to the growing frequency of immunodeficiency-related cancers the authors wanted to report the current knowledge concerning these malignancies. They focus on cancers related to HIV infection or to immunosuppressive treatments given to transplant patients. Cancers hold a special position among numerous severe manifestations occurring during HIV infection. With the correction of immunosuppression due to highly active antiretroviral therapies (HAART) opportunistic infections became rare in HIV-infected patients. Conversely AIDS-defining and non-AIDS-defining cancers remain present but benefit from therapeutical advances. Solid-organ transplantations and allogeneic hematopoietic stem cells transplantations are more and more frequent and efficient. However long term immunosuppressive treatments - to prevent organ rejection - increase the risk of transplant-related cancers. These latter can be treated with standard oncologic therapies. Some of them are able to regress with the reduction or withdrawal of the immunosuppressive treatment.