Purpose: Ocular cicatricial pemphigoid (OCP) is a relatively rare autoimmune disease affecting elderly patients and causing severe symptoms that may culminate in blindness. Treatment is based on immunosuppression, but optimal regimens have not been established. Methods: A prospective unmasked case series of all patients with severe OCP who gave consent and completed treatment and ≥6 months of follow-up in the cornea and immunomodulation outpatient clinics of an academic hospital. Monthly pulses of intravenous cyclophosphamide (IVC; 500 mg) were administered with ondansetron and adjusted according to response. Results: Over 14 years, 13 patients (median age 77 years) met inclusion criteria. All had bilateral OCP (2 eyes were previously blind), but extraocular involvement was rare (1/13). Three to 28 pulses were given, and the patients were followed up for a median of 32 (range, 6-167) months. Remission of inflammation in both eyes was achieved in 12 patients (92%). Vision improved in 5 of 13 patients, stabilized in another 5 (combined, 77%), and worsened in only 3 patients. One patient's condition flared up during treatment that responded to steroids and increasing IVC frequency. In 4 patients and 6 eyes (25%), cicatrization progressed (usually, Foster stages 1-3). Two late relapses occurred and responded to retreatment. IVC was generally well tolerated, although nausea led to modification in 2 patients. One patient developed candida keratitis. Conclusions: Compared with other treatment modalities, low-dose monthly pulse IVC is found to be a relatively safe, simple, and usually effective alternative immunosuppressive treatment in severe OCP.