Secondary malignancies represent an increasing problem for long survivors of primary malignancies treated by chemo- and/or radiotherapy. The occurrence of secondary myelodysplasia and leukaemias after treatment for Hodgkin's disease is well established. Secondary solid tumors are mostly observed following radiation therapy. We report the case of a patient who presented 3 abdominal solid malignancies within 3 years, 29 years after abdominal radiotherapy for a testicular seminoma, namely 2 colon cancers and a peritoneal mesothelioma. Both types of cancer are independently reported in the literature to be more frequent in patients with a history of abdominal radiation than in the general population. To our knowledge there is no other reported case with 3, nearly simultaneously occurring separate solid tumors, which could all be related to former abdominal irradiation. Such a radiotherapy-related long-term side effect should be taken into account when considering adjuvant radiotherapy in patients with low-risk stage I testicular seminoma.