Medical therapy was reduced or withdrawn in 80 of 160 glaucoma patients with normalized intraocular pressure (IOP) after argon lasertrabeculoplasty (ALT). In the 80 patients with unchanged medical therapy, mean IOP was stable during the six-month follow-up period. Timolol could be withdrawn in a significantly smaller proportion of patients [14 of 28 (50%)] compared to pilocarpine [26 of 32 (81%)]. Acetazolamide could be withdrawn in 14 of 20 patients (70%). The mean IOP increase one month after discontinuance of timolol was 6.6 ± 5.7 mm Hg; after pilocarpine, 4.4 ± 4.7 mm Hg; and after acetazolamide, 4.8 ± 6.3 mm Hg. After six months, IOP remained normal in 13 of the 14 patients (93%) from whom timolol had been withdrawn. Corresponding values were 20 of 26 (77%) for pilocarpine and nine of 14 (64%) for acetazolamide. Thus, medicaltherapy could be discontinued in 54% of patients with normalized IOP after ALT without IOP increase to pathological levels for at least six months.