Germ-line p53 mutations are associated with dominantly inherited Li-Fraumeni syndrome (LFS), which features early-onset sarcomas of bone and soft tissues, carcinomas of the breast and adrenal cortex, brain tumors, and acute leukemias. However,carriers of germ-line p53 mutations may also be at increased risk of other cancers. To clarify the tumor spectrum associated with inherited p53 mutations, we examined cancer occurrences among our series of 45 families, plus 140 other affected cases and kindreds reported in the literature. The analyses included all cancers in patients with a germ-line p53mutation and their first-degree relatives with nearly 50% likelihood of being a carrier. Data were abstracted on tumor types and ages at diagnosis in eligible family members, and duplicate reports were excluded. Among 738 evaluable cancers, 569 (77%) were the six tumor types (breast and adrenocortical carcinomas, sarcomas of the bone and soft tissues, brain tumors, and leukemias) associated with LFS. The remaining 169 (23%) cancers included diverse carcinomas of the lung and gastrointestinal tract, lymphomas, and other neoplasms that occurred at much earlier ages than expected in the general population. Unusually early ages at diagnosis are characteristic of hereditary cancers and suggest that carriers of germ-line p53mutations are at increased risk of a wide range of neoplasms. Future studies addressing age-specific penetrance and site-specific cancer risks can increase the utility of LFS as a model for understanding the role of p53 alterations in carcinogenesis and for designing diagnostic and preventive interventions for the broad array of neoplasms in this syndrome.