Purpose To investigate the prevalence and incidence of glaucoma in a large health maintenance organization (HMO) in Israel. Design A population-based retrospective cohort study, conducted using electronic medical database. Methods Collected data included personal and medical characteristics. setting: Maccabi Healthcare Services, the second-largest HMO in Israel, insuring 2 million members and serving 25% of the population with a nationwide distribution. study population: Maccabi members from January 2003 to December 2010. main outcome measures: Prevalence and incidence of glaucoma according to the International Classification of Diseases, 9th revision, Clinical Modification diagnostic codes. Results A total of 15 708 prevalent glaucoma patients were identified among active members of Maccabi in December 2010. A total of 15 332 (97.6%) were 40 years or older, with a point prevalence of 2.2%. Prevalence of glaucoma was strongly associated with age, ranging from 0.28% at age 40-50 to 9.2% among elderly aged 80 or above. The 5 most prevalent diagnoses were open-angle glaucoma (1.61%), exfoliation glaucoma (0.20%), unspecified glaucoma (0.17%), angle closure (0.11%), and normal tension glaucoma (0.06%). We identified 6674 incident glaucoma patients diagnosed between 2003 and 2010. The observed incidence density rate among 40+-year-old members was 1.84 (1.79-1.88) new cases per 1000 person-years. Median age at diagnosis was 64 years old. The risk of glaucoma was similar between sexes up to age 70 years, and was significantly (P <.01) higher in men in older ages. Conclusions Glaucoma affects nearly 10% of the elderly population in Maccabi, with the highest risk of diagnosis at age 70-74. Since glaucoma leads to irreversible vision loss, the present estimates of morbidity should be of significant concern.