OBJECTIVES: To evaluate the cost-effectiveness of ranibizumab versus best supportive care and grid laser photocoagulation therapy in patients with macular edema (ME) secondary to branch or central retinal vein occlusion (BRVO or CRVO). METHODS: A Markov model was developed to compare treatment with ranibizumab to best supportive care (CRVO) and grid laser photocoagulation therapy (BRVO) in patients with ME secondary to RVO.  Data from the BRAVO and CRUISE clinical trials were used to estimate transition probabilities between health states, defined by best corrected visual acuity (BCVA) and the frequency of adverse events.  Costs and utilities from published sources were associated with each treatment and the model health states, and these were combined to predict the incremental costs and outcomes for a cohort treated over a lifetime horizon. The model included the costs associated with fellow eye involvement and the cost of blindness.  A health system perspective in the UK was used. RESULTS: In CRVO, ranibizumab lead to a gain of 0.539 QALYs at an incremental cost of £9,216. The incremental cost-effectiveness ratio (ICER) was £17,103 per QALY. In BRVO, ranibizumab was shown to produce a gain of 0.518 QALYs at an incremental cost of £8,141. The ICER was £15,710 per QALY.   Both results were below the threshold range of £20,000 to £30,000 which is regarded as representing acceptable cost-effectiveness in the UK.  Probabilistic sensitivity analysis suggests that the probability of cost-effectiveness for ranibizumab at a £20,000 threshold is 60% in CRVO and 57% in BRVO. CONCLUSIONS: Ranibizumab is a cost-effective therapy for treating patients with ME secondary to both BRVO and CRVO compared to current standard of care in the UK (laser in BRVO and observation in CRVO).