Introduction and objective: Dilated cardiomyopathy (DCM) is a primary disease of the myocardium, which is one of the three main causes of heart failure and the most common reason for qualifying for transplantation. The criteria for diagnosing left ventricular dysfunction in DCM are quite specific, but there are no clear guidelines regarding right ventricular dysfunction. The objective of the paper was to compare the echocardiographic image of patients with DCM, with special consideration to the function of the right and left ventricles depending on the function of the right ventricle assessed by cardiovascular magnetic resonance imaging (CMR). Material and methods: The study included 29 patients with DCM hospitalized at the Department of Cardiology and Internal Medicine of the Military Institute of Medicine in 2018-2021, in whom other causes of heart failure i.e., advanced coronary artery disease, significant heart defects, pulmonary embolism, and lung pathology were excluded. The right ventricular ejection fraction (RVEF) assessed in CMR was used as the indicator of the reference right ventricular function. Echocardiography was used to determine, among others: right ventricular end diastolic diameter, right ventricular global longitudinal strain, right ventricular fractional area change, left ventricular global longitudinal strain, left ventricular ejection fraction. Results: The right ventricular dysfunction defined as RVEF <45% in CMR, was found in over 50% of patients. Statistically significant correlations were observed between reduced RVEF assessed in CMR and echocardiographic measurements of the right and left ventricle RVEDd (p=0.006), RVGLS (p=0.007), RVFAC (p=0.005) and between-group differences by RVEF for LVGLS (p=0.034) and LVEF (p=0.056). Conclusions: Decreased right ventricular ejection fraction in cardiovascular magnetic resonance imaging revealed correlations with worse right ventricular systolic function and dilatation in echocardiographic evaluation. Right ventricular dysfunction is also associated with impaired left ventricular systolic function expressed as worse longitudinal strain and lower ejection fraction.