Importance: Central retinal artery occlusion (CRAO) is associated with and shares common risk factors with cardiovascular diseases. Over the past several decades, the incidence rates of stroke and ischemic heart disease have substantially decreased in high-income industrialized countries. However, little is known regarding current trends in CRAO incidence rates. Objective: To estimate trends in the incidence rates of CRAO in Korea. Design, Setting, and Participants: This nationwide population-based cohort study was designed on September 7, 2017, and used data from the Korean National Health Insurance Service from January 1, 2002, to December 31, 2015. Individuals with incident CRAO between 2002 and 2015 were identified using the CRAO diagnostic code (H34.1) from the International Classification of Diseases, Tenth Revision. Unadjusted CRAO incidence rates were calculated using the number of CRAO cases identified and the corresponding midyear population, which was obtained from resident registration data. Standardized incidence rates were calculated based on the 2015 census population, and weighted mean annual incidence rates with 95% CIs were computed based on the Poisson distribution. To identify trends in incidence rates, joinpoint regression analysis was performed using standardized incidence rates, and annual percentage changes (APCs) were calculated across the 12-year study period. Data were analyzed from May 1, 2019, to April 30, 2020. Main Outcomes and Measures: Temporal trends in CRAO incidence rates (measured as cases per 100 000 person-years) and age-standardized APCs in CRAO incidence rates using joinpoint and birth cohort analyses. Results: Among 50 million residents of Korea, 9892 individuals (5884 men [59.5%]) with incident CRAO between 2002 and 2015 were identified. The mean age of Korean individuals diagnosed with CRAO was 62.4 years (range, 0-97 years); among men and women, the mean age was 61.5 years (range, 0-96 years) and 63.6 years (range, 0-97 years), respectively. The mean standardized incidence rate of CRAO was 2.00 cases per 100000 person-years (95% CI, 1.97-2.04 cases per 100 000 person-years) among the entire population, 2.43 cases per 100000 person-years (95% CI, 2.37-2.49 cases per 100000 person-years) among men, and 1.61 cases per 100000 person-years (95% CI, 1.57-1.66 cases per 100000 person-years) among women. The highest incidence rate (9.85 cases per 100000 person-years; 95% CI, 9.10-10.60 cases per 100000 person-years) was observed among those aged 80 to 84 years (13.74 cases per 100000 person-years [95% CI, 12.16-15.32 cases per 100000 person-years] for men and 8.04 cases per 100000 person-years [95% CI, 7.21-8.86 cases per 100000 person-years] for women). The incidence rate in the overall study population decreased over time (APC, -3.46%; 95% CI, -4.3% to -2.6%), and this decreasing trend was more evident in women (APC, -4.56%; 95% CI, -5.7% to -3.4%) than in men (APC, -2.90%; 95% CI, -3.9% to -1.9%). The decrease in the incidence rate was more evident among participants younger than 65 years (APC, -6.80%; 95% CI, -8.3% to -5.2%) than among those 65 years and older (APC, -0.57%; 95% CI, -1.5% to -0.4%). Among participants born after 1930, a decrease in the CRAO incidence rate over time was observed in every age group, while the same decreasing trend was not present among those born before 1930. Conclusions and Relevance: This study found that the CRAO incidence rate has been decreasing among residents of Korea, especially among women, individuals younger than 65 years, and individuals born after 1930. This observed decrease may be associated with the development of a national health care system and the general improvement in chronic disease management..