Adenoidcystic carcinoma or cylindroma of the parotid gland is a slow-growing, relentless, and often lethal disease which kills usually by local occurrence and direct extension of the disease. The reported incidence of adenoidcystic carcinoma with reference to other parotid malignancies varies from 5% to 37%. The incidence in this series is 36%. The presence of facial nerve involvement adversely affects the long-term survival. Some authors regard facial nerve involvement as an indication of noncurability. The incidence of local pain is reported to be as high as 50% and is thought to be caused by perineural invasion by the tumor. This is well-documented histopathologically. There is no uniform or standard treatment for this disorder. Extensive resection of the parotid gland (including the facial nerve if there is any indication of involvement), followed by external irradiation to the parotid area and upper neck is the most rational approach to the problem. This is supported both in the review of the literature and from the present series. A radical neck dissection is not included as part of initial therapy unless there are clinically suspicious cervical nodes. Postoperative radiotherapy appears indicated in all cases of adenoidcystic carcinoma of the parotid gland. Four case histories are presented which demonstrate the hallmark characteristics of the disease, i.e. multiple cranial nerve deficits, facial pain and subsequent death by direct intracranial extension of disease. The protracted, relentless course of the disease is well-documented in one case in which 25 local recurrences developed over an 18-year period.