Background <p>Diabetes Mellitus (DM) and Hypertension (HTN) are major public health challenges among older adults. Effective management is crucial to prevent complications and depends on self-care—the activities individuals undertake to manage their health including regular medication adherence.</p> Objective <p>The study objective was to ascertain the prevalence and determinants of self-care practices and medication intake among older adults with DM or HTN in India using nationally representative data.</p> Methods <p>The analysis included data from the Longitudinal Ageing Study in India comprising 8564 and 19,275 individuals previously diagnosed with DM and HTN, respectively. A 7-component self-care activities scale was constructed including items on medication intake, physical activity, diet, tobacco smoking, alcohol consumption, and sleep quality.</p> Results <p>The weighted prevalence of medication intake among patients with DM and HTN was 81.4% (95% CI 79.3, 83.4) and 73% (95% CI 71.7, 74.3), respectively. The mean (SD) self-care activities score in patients with DM and HTN was 4.91 (0.04) and 4.71 (0.02), respectively. On adjusted analysis, individuals aged ≥ 65, never married or widowed, having low or normal BMI, and rural residents had significantly lower odds of medication intake. Furthermore, higher educational attainments, urban residence, being married, and female gender were significantly associated with improved self-care behaviors.</p> Conclusion <p>Lack of medication intake, physical inactivity, tobacco use, and poor sleep quality contribute to lower levels of self-care practices among older adults highlighting the urgent need for health promotion interventions to improve health literacy and healthcare accessibility.</p>