AIM: To compare the efficacy of modified deep sclerectomy combined with Ex-PRESS shunt versus trabeculectomy in primary open angle glaucoma. METHODS: This is a prospective cohort comparative single-center study. Forty-nine eyes of 49 patients were enrolled in the study. Patients were randomly divided into two groups. Group A (22 patients) underwent classic trabeculectomy and group B (27 patients) underwent modified deep sclerectomy combined with insertion of Ex-PRESS model P50 drainage device. RESULTS: Mean age was 69±7y in group A and 64±8y in group B (P=0.03). The mean reduction was 11.1±5.7 mm Hg in group A compared to 15.8±5.7 mm Hg in group B at 6mo (P=0.006), and 9.8±4.9 mm Hg and 15.4±4.7 mm Hg respectively at 1y (P=0.0001). Regarding the postoperative glaucoma medication, significant difference was observed between the two groups (in favour of group B) only at 6mo (P=0.017). At the end of the follow-up period complete success rate in group A was 68.2% compared to 92.6% in group B (χ2 test, P=0.07) and qualified success rate was 100% in both groups. CONCLUSION: Modified deep sclerectomy combined with Ex-PRESS shunt may provide comparable IOP reduction with fewer complications in management of primary open angle glaucoma.