We report a retrospective study of five patients with monocular Fuchs' heterochromic cyclitis associated with an ipsilateral Horner's syndrome. The minimum follow-up was 10 years. The presenting findings were cyclitis in three of the patients and heterochromia iridis associated with blepharoptosis in the other two. The major factors affecting all five patients were cataract and glaucoma. The intraocular pressure was uncontrolled even with maximal therapy, and antiglaucomatous surgery was performed in all cases. A short period of good postoperative control was followed by an intractable ocular hypertension, causing loss of useful vision in all patients. The remarkable combination of Horner's syndrome with glaucoma and their interaction is discussed.