The aim of the study was to assess the atrioventricular, inter- and intraventricular dyssynchrony in patients before and 3 months after biventricular cardiac stimulator implantation (CRT) and to determine the usefulness of echocardiographic parameters in predicting benefit related to CRT. The study group comprised 60 consecutive patients with chronic heart failure (CHF) aged 66,3 ± 8.7 years (57 men - 95%, CHF of ischaemic background - 71.7% and 28.3% of non-ischaemic), with NYHA class III-IV despite optimized pharmacotherapy with QRS > 130 ms, left ventricular end-diastolic diameter ≥ 55 mm and left ventricular ejection fraction ≤ 35%. In the whole studied group decrease of interventricular mechanical delay index (IVMD) was observed. Intraventricular dyssynchrony assessed with septal to posterior wall motion delay (SPWMD) did not alter. Results of the study indicate that echocardiographic assessment of inter- and intraventricular dyssynchrony with colour-coded tissue Doppler imaging parameters and intraventricular dyssynchrony with strain and strain rate parameters is useful in qualification for CRT. These parameters correlate significantly with reduction of left ventricular end-systolic volume or left ventricular ejection fraction.