Purpose: To compare the results of combined non-penetrating deep sclerectomy with phacoemulsification (Phaco-NPDS) to those of non-penetrating deep sclerectomy (NPDS) alone. Materials and Methods: Fifty-two eyes with cataract and primary open angle glaucoma (POAG) or pseudoexfoliative glaucoma (PXG) were randomly assigned to either Phaco-NPDS or NPDS. Follow-up was performed at regular intervals for up to 36 months. Complete success was defined as intraocular pressure (IOP) < 21 mmHg without medication and qualified success was defined as IOP < 21 mmHg with medication. Results: Mean IOP in the Phaco-NPDS group decreased from 23.0 +/- 7.8 mmHg to 14.1 +/- 2.8mmHg and in the NPDS group from 23.5 +/- 5.1 to 14.6 +/- 2.2 mmHg 24 months after surgery. The decreases of IOP in the postoperative period were statistically significant in both groups (p < 0.05). There was no significant IOP difference between Phaco-NPDS and NPDS patients postoperatively (p > 0.05). The mean number of glaucoma medications decreased from 1.8 +/- 1.3 to 0.15 +/- 0.4 and from 1.7 +/- 1.4 to 0.22 +/- 0.6 in the Phaco-NPDS and NPDS groups, respectively. The decreases in the mean number of the anti-glaucoma medications at the end of the postoperative, 24-month follow-up period were found to be statistically significant for both Phaco-NPDS and NPDS groups (p < 0.05). Mean BCVA increased significantly in both groups. However, the visual outcome was significantly better for the Phaco-NPDS group (p < 0.05). The complete and qualified success rates were 65.3% and 88.4% for Phaco-NPDS patients and 73.1% and 92.3% for NPDS patients, respectively (p > 0.05). Conclusion: Phaco-NPDS surgery achieved excellent IOP control, while also providing immediate visual recovery. The success rate was similar to that of the NPDS procedure alone. It is advisable to consider Phaco-NPDS as a primary surgery for patients with coexisting cataract and open angle glaucoma, including PXG.