OBJECTIVES: To evaluate the cost-effectiveness of bimatoprost 0.03% versus a combination product of timolol 0.5% and dorzolamide 2.0% in the treatment of glaucoma. METHODS: A pharmacoeconomic model was constructed based on a 3-month randomized controlled efficacy-trial comparing Lumigan (bimatoprost 0.03%, a prostamide AWP of $53.13) and Cosopt (a fixed combination product of timolol 0.5% and dorzolamide 2.0% AWP of $43.85). The trial evaluated the percent of patients achieving target intraocular pressures (IOPs) throughout the day. The cost of treatment to achieve target was calculated as medication cost/expected effectiveness based on patients achieving a target IOP of <17 mm Hg. Cost-effectiveness was based on three months of the trial treatment RESULTS: With bimatoprost, 30% of patients reached and maintained a target IOP of <17 mm Hg for all measurements throughout the day vs. 17% with the combination product (p<0.05). At three-months, cost-effectiveness ratios were $531 vs. $774 per successful patient for bimatoprost vs. the combination-product. The incremental cost-per additional treatment success with bimatoprost was $214. CONCLUSIONS: Due to a greater percentage of glaucoma patients achieving ideal target treatment goals (considered effectiveness) with bimatoprost 0.03%, bimatoprost monotherapy has a more favorable cost-effectiveness profile than a combination of timolol 0.5% and dorzolamide 2.0%.