Viscocanalostomy, one of the non-penetrating glaucoma surgeries, aims at reducing the intraocular pressure by creating a scleral lake to which aqueous percolates from the anterior chamber and then to the surgically opened ends of the Schlemm’s canal. The Schlemm’s canal is also dilated using high viscosity sodium hyaluronate (2.4%) introduced by a finely polished cannula into its surgically created ostia. Aqueous then leaves the Schlemm’s canal to be drained through the intrascleral and episcleral plexuses of veins into the anterior ciliary veins. Objective: The aim of this study is to evaluate the efficacy and safety of viscocanalostomy in comparison with trabeculectomy as regards the IOP lowering effect, the rate of complications, effect on anterior chamber depth and integrity, effect on the field of vision and the final visual outcome of patients. Patients and methods: Forty eyes of 36 patients with uncontrolled primary open angle glaucoma despite maximally tolerated medical therapy were randomly assigned to receive either trabeculectomy (Group1) or viscocanalostomy (Group2). All patients were unoperated before and no other type of glaucoma (except primary open angle) was included in the study. Follow up after surgery was done on the first day, first week, first month, and then monthly for six months. Results:The results showed a complete success defined as intraocular pressure below 21mmHg without medications in 90% of cases in each group. The percentage of intraocular pressure reduction from its preoperative levels was 62.5% in group1, and 59.8% in group2 on day one postoperatively. By the end of the follow up period, the IOP had dropped by 45.1% in group1, and by 38.1% in group2 from its preoperative levels. The complications were fewer and less serious in the viscocanalostomy group and the anterior chamber integrity was maintained in 95% of eyes, while macroperforation requiring conversion into a standard trabeculectomy occurred only in one eye (5%). Conclusion: Viscocanalostomy offered comparable results to the standard trabeculectomy as regards intraocular pressure reduction effect, while it offered better results as regards its complication rate, its effect on the postoperative field of vision and anterior chamber integrity. It thus has the potential of becoming a safe alternative to the standard trabeculectomy.