Objectives: The aim of our study was to investigate the medical treatment and doses used in patients with a diagnosis of heart failure (HF) and whether these vital drugs were used by cardiologists at the required doses in patients with indications. Patients and methods: This single-center, prospective study included a total of 419 chronic HF (CHF) patients (275 males, 144 females; mean age: 65.2+/-13.8 years; range, 22 to 94 years) between April 1st, 2020 and November 15th, 2020. Patients and their relatives were interviewed and sociodemographic data of the patients were recorded. Routine hematological and biochemical parameters, electrocardiographic findings, electrocardiographic and echocardiographic findings, and systolic and diastolic pressure data were recorded during follow-up. The New York Heart Association (NYHA) functional classes were also determined. Results: The causes of CHF were as follows: 55.6% ischemic heart disease, 33.9% dilated cardiomyopathy (CMP), 3.8% valvular, 1.9% peripartum CMP, 1.9% post-chemotherapy (CT), 1% non-compaction CMP, and 1.9% other causes. The most common reason for not receiving medical treatment at the maximal doses recommended by the guidelines was "not recommended by the physician" (beta-blockers 49.6%, n=208, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers [ACEI/ARBs] 44.6%, n=187, mineralocorticoid receptor antagonists [MRAs] 38.7%, n=162). The second most common reason was the lack of desired follow-ups due to socioeconomic reasons. Conclusion: The most common reason why HF patients do not receive optimal treatment, including beta-blocker, ACEI/ARB, and MRA groups is that clinicians do not recommend it. This study may be a reference to the fact that clinicians' maximal sensitivity in treatment optimization in fragile patient groups, such as HF, would significantly change patient outcomes.