We reviewed available data comparing latanoprost and combined timolol and dorzolamide and the additive effect of latanoprost in patients receiving timolol and dorzolamide in combination using a literature search through the electronic Medline database and presentations from proceedings of recent glaucoma meetings. Several studies have shown that the intraocular pressure (IOP)-lowering effect of latanoprost once a day is equivalent to timolol 0.5% twice a day and concomitant or combined dorzolamide 2% twice a day. Adding latanoprost to timolol and dorzolamide leads to a further 16% reduction of IOP. We conclude that the effect on IOP reduction of latanoprost is similar to combined timolol and dorzolamide, and the additive effect of latanoprost to a combination of timolol and dorzolamide is clinically relevant. In most cases, the overall safety profile of latanoprost is better than combined timolol and dorzolamide.