Purpose To assess the effectiveness and safety of same-site trabeculectomy (TRAB) with mitomycin C (MMC) and Ologen™ (Aeon Astron Europe BV. Leiden, The Netherlands) in patients with a failed non-penetrating deep sclerectomy (NPDS). Methods A retrospective study of 24 consecutive eyes (22 patients) undergoing reintervention by same-site TRAB with at least one-year follow-up after failed NPDS. Mean visual acuity (VA), intraocular pressure (IOP) and use of glaucoma medications were compared before and one year after surgery. Early and late postoperative complications were registered. Kaplan-Meier survival analysis was performed according to four levels of success criteria. Results Overall the mean IOP reduced significantly (24.9 ± 7.1 vs. 14.4 ± 4.5 mmHg; p < 0.001), and the number of glaucoma medications (2.80 ± 1.01 vs. 0.55 ± 0.94; p < 0.001) significantly decreased, one year after surgery. The mean VA remained stable one year after surgery (p = 0.516). Hypotony, defined as IOP ≤ 5 mmHg, in the early postoperative period was observed in 62.5% of eyes, but only in 2 patients (8.33%) in the long term. The mean survival time ranged from 10 months (CI 95% 5–15) to 29 months (CI 95%: 26–32) according to the most stringent and lenient success criteria respectively. Conclusion Same-site TRAB augmented with MMC and Ologen™ may provide an effective, safe and lasting alternative following failed NPDS, especially when sparing of the conjunctiva is highly desirable. Postoperative hypotony is the most common postoperative complication.