Thirty-five phakic eyes from a predominantly black population with clinically uncontrolled open angle glaucoma underwent argon laser treatment to 360 degrees of the trabecular meshwork. The intraocular pressure in the untreated eye was used as a control whenever possible. The mean pressure change in the treated eye at four months showed a decrease of 10.0 mm Hg (P less than 0.001). This effect was maintained throughout the 18-month follow-up period. Thirty-four of the 35 eyes (97%) were clinically controlled with pressures averaging less than 20 mm Hg. The procedure appears to function by improving outflow facility as manifested by a statistically significant increase in outflow for six months post-treatment. The major complication was the formation of peripheral anterior synechiae. These synechiae were localized and did not affect the success of the procedure. Argon laser trabecular surgery appears to be effective in lowering intraocular pressure with many advantages over standard filtering surgery.