To compare the intraocular pressure [IOP] lowering effect of topical drug combination [Latanoprost and Timolol] with Latanoprost alone in patients of Primary Open Angle Glaucoma [POAG] . Randomized controlled Trials [RCT] . Armed Forces Institute of Ophthalmology [AFIO] Rawalpindi from December 2009 to May 2011. A total of 240 eyes of 120 patients [68 males and 52 females] were included in the study. The patients were randomized into two groups of 60 each using random numbers table. Group A [60 patients, 12Q eyes] were put on topical drug combination of Latanoprost and Timolol eye drops and Group B [60 patients, 120 eyes] were treated with topical Latanoprost eye drops alone. IOP assessments were done at baseline, 2 weeks, 4 weeks and 8 weeks intervals after initiation of treatment. Both the groups were age matched with mean age in Group A was 56.39 +/- 8.50 years and in Group B was 55.61 +/- 8.95 years [p=0.09] . Both groups showed significant IOP decrease from the baseline at each follow up interval. However after 8 weeks of start of treatment, pressure lowering effect in group A [14.73 +/- 2.50 mmHg] was significantly more as compared to Group B [9.10 +/- 2.51 mmHg] [p<0.001] . Combination therapy of Latanoprost and Timolol is more effective as compared to monoyherapy with Latanoprost in lowering IOP of patients with POAG