The development of a basal cell carcinoma within a naevus sebaceous of Jadassohn (NSJ) has commonly been reported. However, the development of a squamous cell carcinoma (SCC) is rare. There have been several reports of SCC arising within a NSJ but many contain little or ambiguous clinical information. A thorough review of the current English language literature has identified only three other well documented cases of SCC arising in a NSJ. Of these only one was a case of simultaneous occurrence of squamous and basal cell carcinoma. We report the second case of both malignancies arising within the same NSJ.