We treated selected patients with retinoblastoma with xenon arc photocoagulation between February 1974 and August 1987. Of 790 individual tumors in 410 affected eyes, 45 were treated by this technique. Overall photocoagulation alone was successful in eradicating 76% of the tumors, while in 24% of the tumors additional treatment with cryotherapy, plaque radiotherapy, external beam radiotherapy, or enucleation was necessary. In cases where the tumor was less than or equal to 3.0 mm in diameter and 2.0 mm in thickness and was confined to the sensory retina, without seeding into the adjacent vitreous, tumor destruction was achieved with photocoagulation. The mean number of photocoagulation sessions needed for complete tumor regression was 2.5. Photocoagulation alone was generally unsuccessful for tumors greater than 4.5 mm in diameter and 2.5 mm in thickness, and supplemental treatment with other modalities was often necessary in such cases. Based on observations in these patients, we point out certain misconceptions regarding photocoagulation of retinoblastomas and define our current indications and contraindications for this treatment modality.