Purpose: To describe the clinical outcomes of combined prolene gonioscopy assisted transluminal trabeculotomy (GATT) with phacoemulsification in patients with open-angle glaucoma. Methods: Retrospective study of patients with cataract and open-angle glaucoma treated with GATT and phacoemulsification with intraocular lens (IOL) implantation. Patients with neovascular glaucoma, corneal decompensation, unstable IOL, and with bleeding disorders were excluded. The cumulative probability of failure was the primary outcome. Secondary outcomes were the complete success rate, the mean change on intraocular pressure (IOP), best-corrected visual acuity (BCVA) and number of glaucoma medications at the last follow-up. The frequency of complications was also recorded. Results: Thirty two eyes (25 patients) were included. Nineteen (59.3%) were females, with a mean age of 73.4±12.4 (23–87 years) and a mean baseline BCVA of 1.1±0.75 (0.3–3) LogMAR units. The cumulative probability of failure was 3.2% at 1 month and 6.3% at 6 and 12 months. Sixty-eight and 65.5% of eyes achieved complete success at 3 and 6 months, respectively. The reduction of IOP and number of glaucoma medications at 6 months were statistically significant (p<0.0001 and p=0.0002, respectively). There was a statistically significant improvement of BCVA (from 1.1±0.7 to 0.4±0.7) at 6 months (p<0.0001). IOP spikes (18.7%) and transient hyphema (9.3%) were the most common complications. Conclusion: Combined GATT with cataract surgery reduced the IOP and was associated with low failure rates and few ocular complications. This procedure offers the advantage to avoid the need for a bleb, scleral, or conjunctival incision, allowing the possibility for future glaucoma procedures.