SummaryConjunctival squamous cell carcinoma is an infrequent tumor. It has been reported to occur in association with actinic damage and chronic irritation. To the authors' knowledge, however, this tumor has not been reported secondary to poorly fitting ocular prostheses. Two patients were studied in whom conjunctival squamous cell carcinoma had developed. In both instances, the patient had been enucleated and fitted with an ocular prosthesis more than 40 years before tumor development. Histopathologic evaluation of each tumor revealed its squamous cell origin. In one of the patients, the tumor was found to be metastatic to the ipsilateral parotid gland, an uncommon finding. The authors attempted to identify risk factors that may have contributed to the development of these tumors. Aside from the poor fit of the prostheses, neither patient had significant risk factors for the development of conjunctival squamous cell carcinoma. It is concluded that a new, sanguineous conjunctival discharge or focal eyelid swelling after years of prosthetic wear may not be due to mechanical irritation alone. The onset of these symptoms, especially years after the initial fitting of an ocular prosthesis, should prompt a thorough investigation of its cause.