OBJECTIVE To assess the precipitating factors, clinical course, and treatment of 11 cases of severe intraocular infections of radionecrosis after pterygium excision in an attempt to minimize the devastating ocular sequelae. METHODS From the database of cases of radionecrosis at Royal Perth (Australia) Hospital and Lions Eye Institute, Perth, we identified 11 cases of severe intraocular infection complicating radionecrosis. We reviewed the case notes and the available radiotherapy records (n = 8). METHODS Eleven patients admitted during an 8-year period. RESULTS Mean (+/- SD) dose of radiotherapy was 22.7 +/- 1.0 Gy and mean latency period, 14.45 +/- 2.5 years. Among the six proven bacterial cases, Pseudomonas was identified in four, Staphylococcus aureus in one, and Streptococcus pneumoniae was involved in one bilateral case. Among the four fungal cases, Petriellidium boydii was indicated in two, and Fusarium and Scedosporium inflatum in one each. The condition may remain undiagnosed for some time and mimic a posterior scleritis, serous retinal detachment, or pseudotumor. METHODS Early débridement and culture; close microbiological assistance; and systemic antimicrobials for a prolonged period. Perforation or incipient perforation necessitated penetrating keratoplasties in seven patients and repeated keratoplasties in three. METHODS The use of radiotherapy following pterygium excision should be limited and only low doses used. Ulcer beds and calcific plaques at sites of radionecrosis should not be directly covered without first performing adequate sterilization. Removal of plaques may precipitate sepsis; ulcer beds and plaques harbor infective agents. CONCLUSIONS Severe radionecrosis may expose a patient to a lifelong risk of intraocular sepsis and profound visual morbidity. Conjunctival autografting is a safer method to reduce recurrence rate after pterygium excision.