A TP53 germline mutation, R337H, has been previously described in children from southern Brazil with adrenocortical tumours but no documented familial history of other cancers. Here, we have screened for TP53 mutation 45 Brazilian unrelated individuals with family histories fulfilling the clinical definitions of Li-Fraumeni (LFS) or Li-Fraumeni-like (LFL) syndromes. Mutations were found in 13 patients (28.9%), including six (46.1%) R337H mutations, and four novel germline mutations (V173M, V197M, G244D and IVS6+1G>T). Families with the R337H mutation presented a wide spectrum of tumours, including breast cancers (30.4%), brain cancers (10.7%), soft tissue sarcomas (10.7%) and adrenocortical carcinomas (8.9%). Testing of 53 Brazilian subjects with no cancer history showed that R337H was not a common polymorphism in that population. Moreover, loss of heterozygocity with retention of the R337H allele was observed in a breast adenocarcinoma, supporting a role for this mutation in breast tumorigenesis. These results show that the TP53 R337H germline mutation predisposes to a larger spectrum of tumours, similar to the one reported for other TP53 mutations.