Adenomatous lesions of the temporal bone are seldom encountered in clinical practice. Four cases of primary adenocarcinoma of the middle ear are reported. All four patients presented with a mass behind an intact tympanic membrane. Two of the four patients had received radiation to the head and neck area 10 or more years prior to their developing adenocarcinoma of the middle ear space. Although this tumor is locally invasive, it does not appear to be highly aggressive and can be treated by local excision, i.e., mastoidectomy with tympanoplasty.