OBJECTIVE The aim of this study was to evaluate the ocular discomfort of brinzolamide 1%/timolol 0.5% ophthalmic suspension fixed combination dosed twice-daily compared to dorzolamide 2%/timolol 0.5% ophthalmic solution fixed combination dosed twice-daily. METHODS This was a prospective, double-masked, parallel-group, randomized, clinical trial. Patients had open-angle glaucoma or ocular hypertension and were randomized to twice-daily therapy with either brinzolamide 1%/timolol 0.5% or dorzolamide 2%/timolol 0.5%. Patients completed ocular discomfort assessments (based on burning, stinging, a feeling of heat or warmth, sharp pain, or smarting pain) on their current intraocular pressure-lowering therapy at baseline and on study medication after 1 week of dosing. RESULTS In the intent-to-treat analyses, mean ocular discomfort scores at 1 week were significantly lower in eyes receiving brinzolamide 1%/timolol 0.5% than dorzolamide 2%/timolol 0.5% (0.77 vs. 1.53; P = 0.0003). Mean increases from baseline in ocular discomfort scores were statistically significant in both groups but were smaller in eyes receiving brinzolamide 1%/timolol 0.5% (0.49; P = 0.0028) than dorzolamide 2%/timolol 0.5% (1.32; P < 0.0001). Over threefold more patients on brinzolamide 1%/timolol 0.5% (23/47, 49%) than dorzolamide 2%/timolol 0.5% (7/47, 15%) reported no ocular discomfort after 1 week of therapy (P = 0.0004). CONCLUSIONS Brinzolamide 1%/timolol 0.5% ophthalmic suspension is associated with a statistically significantly less ocular discomfort profile than dorzolamide 2%/timolol 0.5% ophthalmic solution.