Sang Geun Bae,1 Sin Kam,2 Ki Soo Park,3,4 Keon-Yeop Kim,2 Nam-Soo Hong,2 Ki-Su Kim,2 Yu-mi Lee,2 Won Kee Lee,2 Michael Sung Pil Choe5 1Department of Preventive Medicine, Regional Cardiocerebrovascular Disease Center, Kyungpook National University Hospital, 2Department of Preventive Medicine, Kyungpook National University School of Medicine, Daegu, 3Department of Preventive Medicine and Institute of Health Sciences, Gyeongsang National University School of Medicine, 4Department of Preventive Medicine, Regional Cardiocerebrovascular Disease Center, Gyeongsang National University Hospital, Jinju, 5Department of Emergency Medicine, CHA Gumi Medical Center, CHA University, Gumi, Korea Purpose: We assessed medication nonadherence, categorized as intentional or unintentional, and related factors in elderly patients with hypertension, correlating the data with measurement of blood pressure as the final target of medication adherence and other possible influencing factors, such as lifestyle. Patients and methods: Subjects were aged ≥65 years, resided in a rural area, and were taking antihypertensive drugs. The survey was conducted in July 2014. Participants were divided into the following three groups: “Adherence”, “Unintentional nonadherence”, and “Intentional nonadherence”. Individual cognitive components, such as necessity and concern as well as self-efficacy and other related factors, were compared according to adherence groups. The interrelationships between those factors and nonadherence were tested using structural equation modeling analysis. Results: Of the 401 subjects, 182 (45.6%) were in the adherence group, 107 (26.7%) in the unintentional nonadherence group, and 112 (27.9%) in the intentional nonadherence group. Necessity and self-efficacy were found to have a significant direct influence on unintentional nonadherence behaviors (necessity β=–0.171, P=0.019; self-efficacy β=–0.433, P