More than 50% of people living with congestive heart failure have diastolic heart failure (DHF). Most of them are older than 70 years, and female. The prevalence of DHF has increased with time. DHF is caused by left ventricular (LV) diastolic dysfunction (DD) which is induced by diastolic dyssynchrony. Cardiac and extracardiac factors play important roles in the development of heart failure (HF) symptoms. The diagnosis of DHF is generally based on typical symptoms and signs of HF, preserved or normal LV ejection fraction, DD and no valvular abnormalities on examination, using noninvasive and invasive methodologies. The outcomes with pharmacological therapy in patients with DHF are frequently neutral in clinical trials, and prognosis still remains poor with a 5-year mortality of 42.3% after hospitalization for HF. Further trials are necessary.