Three cases of contemporaneous acute myeloid leukaemia (AML) and sarcoidosis are described. The possible pathogenic mechanisms concerning their concurrent appearance are discussed: if sarcoidosis impaired T-cell response, it could perhaps predispose the development of AML; alternatively, the development of sarcoidosis during AML may be due to a reaction linked to a diffuse release of tumour antigens with a subsequent formation of a non-caseating granulomata.