Background: there is a growing experience that dilated cardiomyopathy is in a substantial part a result of myocardial inflammation.The diagnostics of inflammatory cardiomyopathy (ICM) is based not only on clinical data and echocardiographic findings, but mainly on the results of endomyocardial biopsy (EMB).Classical histological assessment is insufficient; there is an absolute necessity of imunohistological and genetical evaluation focused on the detection of nucleic acids of potential patogens in endomyocardial biopsy (EMB) specimens.Patients group: there were 24 patients with the suspicion on ICM evaluated since December 2009 till October 2010.In 3 cases we found an alternative etiology of left ventricle systolic dysfunction, so only 21 patients were finally included into the assessment.The mean age was 40 14 years, 6 of the patients were women, time since the first symptoms was 2.6 2.3 months.Left ventricle ejection fraction was 22 6 %, NYHA class 2.8 0.4.Methods: ICM was defined as the presence of 14 leucocytes (LCA+) and/or 7 T-lymphocytes (CD3+)/mm2 in EMB samples.Polymerase chain reaction (PCR) assays for detection of viral genome were focused on parvovirus B19,human herpes virus-6, enterovirus, adenovirus, cytomegalovirus, Ebstein-Baar virus, and on borrelia burgdoferi genome.Results: immunohistological evidence oflCM was found in 15 cases (71%).In 8 of these 15 cases, the results were positive for both CD3+ and LCA+ cells (that is 38% of all cases); remaining 7 cases were only LCA+ positive.The presence of viral genome in the myocardium was detected in 10 cases (i.e.48%).In the group of proven ICM, the PCR was positive in 8 of 15 cases (53%).Conclusion: the role of EMB in the diagnostics of ICM is crucial.Recent DCM very often has an inflammatory basis.Immunosupresive therapy was limited to 1/3 of our ICM cases because of the presence of viral nucleic acid in the myocardium.