A patient with chronic unilateral conjunctivitis of six years' duration was discovered to have sebaceous carcinoma of the eyelid. This case is in many respects typical of the delay between onset and diagnosis frequently seen in this disease. Our case is unique, however, because it demonstrates that if not specifically alerted to the possibility of malignancy, even the experienced ophthalmic pathologist may misdiagnose. The factors necessary for early diagnosis of this disease are: (1) suspicion on the part of the clinician, (2) adequate surgical biopsies, and (3) examination of the biopsy specimen by an experienced pathologist who has been alerted to look for malignant changes.