Subconjunctival 5-fluorouracil has been an effective adjunct in glaucoma filtering surgery. We investigated the effectiveness of 5-fluorouracil in primary trabeculectomy combined with phacoemulsification and posterior chamber intraocular lens implantation (glaucoma triple procedure). Seventy-four patients were enrolled and randomly assigned into two groups to receive either no 5-fluorouracil (control patients) or low-dose 5-fluorouracil (mean total dose, 24.8 mg; mean number of injections, 5.0 +/- 1.3). The mean preoperative intraocular pressure was 20.1 +/- 5.4 mm Hg for the 5-fluorouracil group and 21.0 +/- 5.2 mm Hg for the control group (P = .48, Student's unpaired t-test). The mean number of medications was 2.2 +/- 1.0 and 2.0 +/- 1.0 (P = .49, Mann Whitney U test), respectively. At all postoperative visits, there were no statistically significant differences in mean intraocular pressures between the two groups. Mean follow-up was 13.2 months for 5-fluorouracil-treated patients and 15.0 months for control patients. At the last postoperative visit, mean intraocular pressures were 15.4 +/- 3.7 mm Hg and 15.0 +/- 5.0 mm Hg, respectively (P = .45, Student's unpaired t-test). Both groups showed comparable visual outcome (20/40 or better in 31 of 38 5-fluorouracil-treated patients [82%] vs 32 of 36 control patients [89%]) and a decrease in number of medications needed, 0.7 +/- 1.0 and 0.7 +/- 0.9, respectively (P = .96, Mann Whitney U test). Thus, 5-fluorouracil administered as in our study did not seem to have any effect in primary trabeculectomy combined with phacoemulsification and posterior chamber intraocular lens implantation.