BACKGROUND: Thyroid hormone plays a key role in cardiovascular diseases (CVDs), and stress may impact this relationship by affecting cortisol and triiodothyronine (T3) levels. This study explored the association between stress, indicated by cortisol levels, and thyroid function in cardiovascular patients, particularly those with hypertension. METHODS: A cohort of 87 cardiovascular patients (37 females, 50 males) and 60 healthy controls (28 females, 32 males) was analyzed. Patients included those with coronary artery disease, acute myocardial infarction, and a high proportion with anterior wall myocardial infarction (AWMI, 52%). Anthropometric data and blood samples were collected, and cortisol and T3 levels were measured using the radioimmunoassay method. Blood pressure measurements were also recorded to assess associations with cortisol, thyroid function, and hypertension. RESULTS: Cardiovascular patients had significantly higher cortisol levels (1065.99 ± 700.54 ng/mL vs 768.35 ± 563.10 ng/mL, CONCLUSION: This study found significant associations between elevated cortisol and reduced T3 levels in cardiovascular patients, particularly those with hypertension. Although stress-induced thyroid dysfunction remains a hypothesis, these findings suggest a potential link between cortisol, T3, and CVD. Further longitudinal research is needed to explore causal mechanisms.