Introduction Cardiothyreosis is associated with higher morbidity and mortality than other forms of hyperthyroidism. The aim of our study was to identify its therapeutic and evolutive aspects in an adult population of southern Tunisia. Methods Retrospective study including all cases of cardiothyreosis followed in our department during a period of 20 years. Results 100 cases of cardiothyreosis were collected. To treat the hyperthyroidism, the association of antithyroid drugs and radioactive iodine was used in 52%of patients. Thyroidectomy was performed in 9%of cases. For the cardiothyreosis, 90%of patients went under ß-blockers. All patients with congestive heart failure (CHF) were treated with diuretics. Patients with atrial fibrillation have received anticoagulants. The most used molecule was acenocoumarol (86%). The evolution of cardiothyreosis was favorable in 64.4%of cases while 9%of patients died. In our study, the association of atrial fibrillation and CHF in the same patient, and the elevation of the end-systolic and end-diastolic diameters of the left ventricular were significantly associated with higher risk of mortality (P < 0.05). Conclusion While its diagnosis is often easy, the management of cardiothyreosis remains difficult. The prognosis of this disease may be ameliorated by an early and efficient treatment.