PurposeThe aim of this study was to assess medication adherence and its related factors among elderly people living alone with chronic diseases using a conceptual framework with the Belief about Medicines Questionnaire and the Adherence to Refills and Medication Scale-Korean version.Participants and methodsThis was a cross-sectional study conducted in 3,326 elderly people living alone, who were enrolled in Seongnam Center for Home Health Care in South Korea. They completed validated questionnaires assessing their adherence and beliefs about medication in general.ResultsIn attitudinal analysis using Belief about Medicines Questionnaire, 37.0% of patients were accepting of medication (high necessity with low concerns), 49.7% were ambivalent (high necessity with high concerns), 1.9% were skeptical (low necessity with high concerns), and 11.4% were indifferent (low necessity and low concerns). In multivariable analysis, we found that adherence was related to patients’ beliefs about medication; compared with patients who were accepting of medication, those in the other three attitudinal groups had significantly lower adherence (indifferent, p=0.003; skeptical, p=0.001; ambivalent, p<0.001). Also, low adherence was associated with heavy burden of drug costs (β=0.109; 95% CI 0.03, 0.19), presence of drug side effects (β=0.431; 95% CI 0.11, 0.75), dissatisfaction with medication (β=−0.626; 95% CI −0.77, −0.48), perceiving health status as poor (β=−0.151; 95% CI −0.27, −0.03), and receiving medical aid (β=0.655; 95% CI 0.42, 0.89). Gender, age group, and number of prescribed medication were not associated with medication adherence.ConclusionTo improve medication adherence of elderly living alone, it is essential to identify barriers to adherence, including their concerns and attitudes toward medications. These factors associated with adherence should be considered in further intervention studies.