Background: The risk of a subsequent cancer is an important issue for patients with melanoma. The development of a second primary cancer in patients with a solitary melanoma has been discussed in several studies. However, to our knowledge, the incidence of second primary cancer (SPC) in patients with multiple primary melanoma (MPM) has not been thoroughly investigated., Aim: To quantify the incidence of SPC in patients with MPM, with the aim of possibly developing further preventive measures., Methods: In a retrospective study, 76 patients with MPM were identified from 2155 patients being followed up at our unit., Results: Of the 76 patients, 12 (16%) developed another neoplasm, with 59% of them having nonmelanoma skin cancer (NMSC), and 41% other noncutaneous cancers. By contrast, only 8% of those with single primary melanoma had other neoplasms (21% of whom had NMSC)., Conclusions: Patients with MPM, especially men with skin phototype II, have a significantly increased incidence of developing SPC, particularly NMSC. Thus, careful monitoring is essential not only to detect recurrence of the original cancer or development of another primary melanoma, but also development of new malignancies of different types, particularly NMSC., (© The Author(s). CED © 2012 British Association of Dermatologists.)