OBJECTIVE To study the incidence, aetiology, pathogenic causes, treatment and visual outcomes of endophthalmitis (EO) at the Department of Ophthalmology, Oslo University Hospital (OUS), Norway. METHODS Retrospective registry study. Medical records of all EO patients treated at OUS over a 2-year period were reviewed. RESULTS The study identified 46 EO eyes of 44 patients; 19 eyes had postcataract surgery EO (PCE), and 6 eyes had postinjection EO (PIE). Of 4778 primary cataract surgeries performed at OUS, there was one PCE (incidence 0.21 per 1000; 95% CI 0.04-1.19 per 1000). Of 38 134 intravitreal injections performed at OUS, there were 3 PIE (incidence 0.08 per 1000; 95% CI 0.03-0.23 per 1000). Among 15 751 cataract surgeries performed at other ophthalmic centres in Oslo and Akershus County (OOC), there were 15 PCE (incidence 0.95 per 1000; 95% CI 0.58-1.57 per 1000). Of 3000 intravitreal injections performed at OOC, there was one PIE (incidence 0.33 per 1000; 95% CI 0.059-1.89 per 1000). For neither PCE nor PIE, there were significant differences in odds ratios between OUS and OOC. The odds ratio for PCE versus PIE was, however, 8.0 (95% CI 2.7-24.0; p < 0.001). Cultures were positive in 35 of 46 eyes (76%). The most common pathogen was Staphylococcus epidermidis. Twenty-two eyes (48%) achieved a clinically significant improvement in visual function (≥0.3 logMAR) following treatment. CONCLUSIONS The overall risk of PCE and PIE was low. It was, however, higher for PCE than PIE, probably reflecting the relative difference in invasiveness between the procedures.