Purpose: To analyze the results of trabeculectomy in patients with primary angle-closure glaucoma. Methods: A retrospective and noncomparative case series analysis was pet-formed oil data from Taiwan, from 2001 to 2004, The outcomes of trabeculectomy in eyes with acute primary angle-closure glaucoma attack (AACG) and those with chronic primary angle-closure glaucoma (CACG) were assessed in terms of final intraocular pressure (IOP), changes to visual acuity, and the incidence of complications. Results: A total of 52 eyes of 52 patients, 15 patients in AACG group and 37 patients in CACG group, were reviewed. The mean follow-tip period was 32 months (range, 26-42 mo). In terms of no visual acuity change after surgery, there were significant differences between the CACG and AACG groups (P = 0.02, Fisher exact test). In terms of Final IOP control, trabeculectomy outcome was significantly worse in patients in the AACG group than those in the CACG group (P < 0.01, Fisher exact test). Moreover, the complication of bleb encapsulation appeared more frequently in the AACG group than in the CACG group (P = 0.02, Fisher exact test). Conclusions: Compared with CACG, trabeculectomy may not be as good for patients of AACG, because it may lead to worsened visual acuity; it also seems to present a greater failure rate, more complications, and fewer cases of surgical survival.