AIM: To evaluate the efficacy and tolerability of the fixed combination of bimatoprost 0.03% and timolol 0.5% (BTFC) in patients in Greece with primary open angle glaucoma (POAG) or ocular hypertension (OHT) whose previous therapy provided insufficient lowering of intraocular pressure (IOP). METHODS: A multicenter, prospective, open-label, non-interventional, observational study of the use of BTFC in clinical practice was conducted at 41 sites in Greece. The primary endpoint was the reduction in IOP from baseline at study end, approximately 12wk after initiation of BTFC therapy. RESULTS: A total of 785 eligible patients were enrolled in the study and 97.6% completed the study. The mean±SD IOP reduction from baseline at 12wk after initiation of BTFC was 6.3±2.8 mm Hg (n=764; P<0.001). In patients (n=680) who replaced their previous IOP-lowering monotherapy (a single drug, or a fixed combination of 2 drugs in a single ophthalmic drop) with once-daily BTFC, the mean±SD IOP reduction from baseline at 12wk was 6.2±2.8 mm Hg (P<0.001). IOP was reduced from baseline in 99.2% of patients, and 58.0% of patients reached or exceeded their target IOP. Substantial mean IOP reductions were observed regardless of the previous therapy. BTFC was well tolerated, with 96.0% of patients who completed the study rating the tolerability of BTFC as “good” or “very good.” Adverse events were reported in 8.3% of patients; only 0.6% of patients discontinued the study due to adverse events. CONCLUSION: In clinical practice in Greece, BTFC is well tolerated and effectively lower the IOP in patients with POAG or OHT who requires additional IOP lowering on their previous therapy.