The authors treated corneal neovascularization in 25 eyes of 23 patients with corneal laser photocoagulation using 577 nm yellow light. Four groups of patients were treated: patients with corneal neovascularization and active graft rejection (group 1); patients with neovascularization before penetrating keratoplasty (PK) (group 2); lipid keratopathy patients with opacification and/or focal edema threatening the visual axis (group 3); and patients with extensive corneal neovascularization, who were not candidates for PK (group 4). Area of neovascularization and clinical outcome were monitored. After corneal laser photocoagulation, there was a statistically significant reduction in the neovascularized area in group 1 from 32% of corneal area to 10%, and in group 3 from 46% to 27%. All five patients in group 1 had resolution of their graft rejection. In group 3, there was a reduction in the area of corneal opacification from 59% of corneal area to 52%. This difference was not statistically significant. Seven of nine patients in group 3 had stabilization or improvement in their vision over a mean of 9.3 months follow-up. There was no significant change in neovascularized area in groups 2 and 4. In group 2, no rejection reactions occurred over a mean of 5.6 months follow-up after PK. In group 4, corneal laser photocoagulation was disappointing.