Aim. This study aimed to assess medication adherence among older people with coronary heart disease and its relationship with hospitalizations. Methods. This is a prospective cohort study conducted at the outpatient clinics of a major hospital in Vietnam from November 2022 to June 2023. Consecutive older patients with coronary heart disease were recruited and followed for 6 months. Medication adherence was defined using the five‐item Medication Adherence Report Scale (MARS-5). Multivariable logistic regression models were applied to examine the impact of medication adherence on hospitalization due to cardiovascular disease (CVD) and all-cause hospitalization. Results. There were 643 participants. They had a mean age of 73 (SD 8), and 74.3% were male. Overall, 76.4% (491/643) were classified as “adherence”. Over 6 months follow-up, 23.3% of the participants admitted to hospital and of these, 9.2% were due to CVD. The CVD hospitalization rate was significantly lower in the adherence group compared to the non-adherence group (7.7% versus 13.8%, p = 0.023, respectively). In logistic regression models, medication adherence was associated with a significant reduced likelihood of CVD hospitalization (adjusted OR 0.48, 95%CI 0.27 – 0.86). Medication adherence was also associated with a trend of reduced all-cause hospitalization (adjusted OR 0.75, 95%CI 0.49 – 1.15). Conclusions. This study showed a positive relationship between medication adherence and reduced risk of CVD hospitalization in older people with coronary heart disease. Healthcare providers should consider incorporating adherence assessment into the long-term care for older patients with coronary heart disease.