The São Tomé white-toothed shrew Crocidura thomensis is endemic to the island of São Tomé in the Gulf of Guinea. This species was discovered in 1886 and since then has been recorded from fewer than 10 locations. This paper summarizes all published and unpublished information on C. thomensis. The species is currently listed by the IUCN as ‘Insufficiently Known’, but using the new IUCN Red List Categories is re-classified as ‘Vulnerable B1 + 2c’. Threats to the survival of C. thomensis include deforestation, plantation redevelopment and predation by introduced mammals.