To evaluate the incidence and risk factors for secondary solid tumors in Japan after allogeneic hematopoietic SCT (allo-HSCT), 2062 patients who had received allo-HSCT between 1984 and 2005 were retrospectively analyzed. Twenty-eight patients who developed 30 solid tumors were identified a median of 5.6 years after transplantation. The risk for developing tumors was 2.16-fold higher than that of the age- and sex-adjusted general population. The cumulative incidence of solid tumors at 10 years after allo-HSCT was 2.4%. The risk was significantly higher for tumors of the skin, oral cavity and esophagus (standard incidental ratio 40.23, 35.25 and 10.73, respectively). No increase in gastric, colon or lung cancer, despite being the most prevalent neoplasm in the Japanese, was observed. In multivariate analysis, occurrence of chronic GVHD and malignant lymphoma as a primary disease was associated with a higher risk for developing solid tumors. Eighteen patients are still alive, and their 5-year probability of survival since diagnosis of solid tumors is 59.7%. Our data suggest that the incidence and risk factors of secondary solid tumors in Japanese allo-HSCT recipients are comparable to those reported in Western countries and emphasize that the early detection of solid tumors has a crucial role in improving OS.