Purpose: This methodological study evaluated the psychometric properties of the Self-Care of Coronary Heart Disease Inventory version 3 (SC-CHDI v3) in a Korean context. Methods: The SC-CHDI v3 was translated into Korean following a rigorous translation process. Participants were 452 patients who had experienced coronary heart disease (CHD), all recruited from a tertiary hospital in Korea. Exploratory and confirmatory factor analyses were performed to test construct validity. Concurrent validity was examined by correlating scores from the Korean version of the SC-CHDI v3 with those from the Cardiac Self-Efficacy Scale. Internal consistency was analyzed using Cronbach's alpha and McDonald's omega. Results: The Korean version of the SC-CHDI v3 consists of 21 items, excluding two from the original instrument. The self-care maintenance subscale identified a two-factor structure: “treatment adherence” and “health-promoting behaviors.” The goodness-of-fit indices were satisfied: χ2 = 18.19, p = .110, comparative fit index (CFI) = .97, Tucker-Lewis Index (TLI) = .95, and standardized root mean square residual (SRMR) = .04. The self-care monitoring subscale consisted of a one-dimensional structure (“monitoring behaviors”) and the goodness-of-fit indices were satisfied: χ2 = 19.19, p = .059, CFI = .99, TLI = .99, and SRMR = .04. The self-care management subscales had a two-factor structure of “consulting behaviors” and “problem-solving behaviors.” The goodness-of-fit indices were satisfied: χ2 = 16.44, p = .037, CFI = .99, TLI = .98, and SRMR = .03. Scores from the Cardiac Self-Efficacy Scale showed a positive correlation with the Korean version of SC-CHDI v3 subscales. Reliability estimates were ≥ .80 for all subscales except for the self-care maintenance subscale. Conclusions: The Korean version of the SC-CHDI v3 consists of 21 items in 3 subscales and is a valid and reliable instrument. Therefore, healthcare providers can effectively utilize it to assess the self-care levels of patients with CHD.