The aim of the paper is to investigate the utility of left atrial longitudinal strain (LALS) in the diagnosis of heart failure with preserved ejection fraction (HFpEF) when left ventricular diastolic function is indeterminable and the assessment of natriuretic peptides is not routinely performed.Method. The study included 180 patients with signs and symptoms suggestive of non-acute heart failure, examined clinically and echocardiographically, both conventionally and via speckle tracking method.Results. 33 patients had a normal echocardiographic examination. Diastolic dysfunction (DD) was present in 116 patients of whom 32 patients had grade I, 66 patients grade II, 18 patients grade III DD. Diastolic function could not be determined in 31 patients. The mean value of LALS and NTproBNP in patients with normal echocardiography was significantly different from the group with DD for both variables (p<0.001). LALS was inversely correlated with the grade of DD (r=-0.83, p<0.001). The cut-off value of LALS for predicting DD was 25%. Applying this value in patients with indeterminate diastolic function we identified 21 patients with HFpEF (p<0.001).Conclusions. LALS can help in the diagnosis of HFpEF when other echocardiographic criteria are irrelevant and NTproBNP is not routinely performed. LALS was correlated with the presence and severity ofDDwith a cut-off value of 25%.