Background <p>Shared decision-making has been shown to improve self-management of chronic diseases, however whether it improves the medication adherence of chronic disease patients and the magnitude of the effect remains unclear. Therefore, our objective was to evaluate whether shared decision-making is associated with better adherence and to estimate the magnitude of this association.</p> Methods <p>We conducted a community-based cross-sectional questionnaire survey in four areas of Hubei, China (April–June 2021) using cluster sampling. Medication decision-making was assessed with the Control Preferences Scale–Post, and medication adherence with the 4-item Morisky Medication Adherence Scale (MMAS-4). We estimated associations using propensity-score weighting and logistic regression. We investigated three types of medication decision-making models: paternalistic model, shared decision-making model, and self-decision-making model. The predictor of interest in this study is the models of medication decision-making, and the dependent variable was patients’ medication adherence. We applied the propensity score weighting approach to adjust for observed differences in characteristics between those with different types of medication decisions, and explored the association between medication decision-making and medication adherence through logistic regression.</p> Results <p>Patients with self-decision-making were less likely to be adherent to medication (OR = 0.33, 95%CI:0.27–0.41) compared to those with shared decision-making, and the corresponding marginal effect was − 0.278 (OR = 0.331, 95%CI: -0.292,-0.203). There was no significant difference in medication adherence between patients with shared decision-making and patients with a paternalistic model. Patients over 80 years old (OR = 2.19, 95%CI: 1.44–3.39), with two or more diseases (OR = 1.24, CI: 1.03–1.49), with high medication knowledge (OR = 1.32, 95%CI: 1.09–1.63), who have not experienced adverse drug reactions (OR = 1.89, 95%CI:1.53–2.33), or often visit non-primary medical institutions (OR = 1.93, 95%CI: 1.58–2.34) were more likely to be adherent to medication. While patients in bad health status (OR = 0.73, 95%CI: 0.61–0.87), who smoke (OR = 0.77, 95%CI: 0.60–0.99), seldom do exercise (OR = 0.83, 95%CI: 0.70–0.98), taking five or more medicines (OR = 0.63, 95%CI:0.51–0.78), have difficulty in taking medication (OR = 0.65, 95%CI: 0.48–0.86), seldom communicate with doctors (OR = 0.79, 95%CI: 0.64–0.95), and lack trust in doctors (OR = 0.79, 95%CI: 0.66–0.95) were less likely to be adherent to medication.</p> Conclusion <p>Shared decision-making may be included in intervention measures designed to reduce non-adherence in patients with hypertension or diabetes in China.</p>