ABSTRACT.Purpose: To determine the efficacy and safety of needling revision of failed filtering blebs. Methods: We reviewed retrospectively 26 eyes that had undergone needling revision for a failed trabeculectomy. The needling revisions were performed either with adjunctive use of Mitomycin C, 5-Fluorouracil or without antimetabolites. The procedure was usually performed as a clinic procedure, using a 27-gauge needle.Results: The mean follow-up time was 14.5 AE 11.3 months (range 6.0-48.0 months). Intraocular pressure (IOP) decreased from 28.8 AE 6.8 mmHg (range 19.0-40.0 mmHg) to 15.3 AE 5.2 mmHg (range 7.0-35.0 mmHg). Twelve eyes (46.2%) achieved success, defined as IOP 18 mmHg without medication; 11 eyes (42.3%) achieved qualified success, defined as IOP 18 mmHg with antiglaucomatous medication, and three of 26 eyes (11.5%) were classified as failures. The success rate after the initial needling was 64% at 6 months and the same after 1 year and 2 years. The success rate after one or more needlings was 96% at 6 months and 77% at 1 year and 2 years. Complications developed in six of the 26 eyes (23.1%). These involved transient corneal epithelial defects in three eyes (11.5%), temporary conjunctival wound leak in two eyes (7.7%), and development of bullous keratopathy in one high risk eye (3.8%). Conclusion: Our results are comparable to the results of other studies. Needling revision appears to be a useful tool in the management of glaucoma.