Diastolic heart failure (DHF), i.e. heart failure with preserved left ventricular ejection fraction, is poorly explored field of cardiology, with a high degree of uncertainty. This refers to prognostic evaluation too. One-year mortality in DHF has been reported in very wide range from 1.3 % to 24 %. This considerable variance is due to non-uniform definition of DHF, different characteristics of the studied populations, various heart failure etiologies and therapy. Previous studies comparing the prognosis of DHF and systolic heart failure (SHF) have not been definitely conclusive. The comparison is complicated by many differences in methodology of the studies. Some trials have shown better survival for DHF while others have not found significant differences. Smaller studies have almost entirely failed to prove prognostic difference. Larger studies, registries and metaanalyses mostly demonstrated significantly more favourable life prognosis for DHF. DHF and SHF fundamentally differ in the evidence based medicine regarding pharmacotherapy. Unlike SHF there exists no therapy significantly improving prognosis of DHF. Alarming fact is that the prognosis of DHF over the past 20 years has not improved.