OBJECTIVE: To evaluate the short-term efficacy and safety of needle revision of failed filtering blebs augmented with subconjunctival injection of mitomycin C. PATIENTS AND METHODS: Needle revision of failed filtering blebs followed by subconjunctival injection of 10 to 20 μg of mitomycin C was performed in 41 eyes. Short-term results were analyzed 6 months postoperatively. RESULTS: The mean (± Standard deviation [SD]) intraocular pressure decreased from 26.4 ± 6.2 to 16.4 ± 6.5 mm Hg (P < .001), and the mean (± SD) number of medications decreased from 2.8 ± 1.4 to 0.7 ± 1.1 (P < .001). The overall success rate (defined as intraocular pressure between 5 and 21 mm Hg and no serious complications) was 76%. Initial intraocular pressure, number of previous surgical procedures, type of glaucoma, and lens status did not influence the success rate. The resulting bleb was significantly larger in the successful cases (2 ± 0.8 vs 0.33 ± 0.5; P < .001). Complications included one case of late suprachoroidal hemorrhage. The mean (± SD) visual acuity remained stable (delta visual acuity in Snellen lines = 0.023 ± 1.1). CONCLUSION: Needle revision followed by subconjunctival injection of mitomycin C is an alternative to more complicated surgical procedures in cases of failed filtering blebs. Bleb formation was essential for successful reduction of intraocular pressure, which suggests subconjunctival injection of mitomycin C by itself may not lower intraocular pressure.