Dilated cardiomyopathy (DCM) is the most common type of cardiomyopathy, with a reported annual incidence of 0.57/100,000 children, with high morbidity and mortality in infants. The etiology of DCM is heterogeneous, including genetic mutations present in about 35% of patients, mostly in familial forms. Exact data on the share of genetic etiology in pediatric DCM are limited, although studies in adults have shown an important clinical impact of early detection of genetic defect. The aim of the study was to elucidate the importance of genetic testing in children with DCM phenotype for personalized therapeutic and prognostic decisions. Compared to the clinical presentations in adult’s patients, pediatric DCM is often asymptomatic initially, but remains the leading cause of heart failure and heart transplantation 5 years after diagnosis. Current guidelines indicate the need for genetic counseling in the first step of diagnosis. However, the identification of genetic mutations remains difficult due to genetic etiological features (type of inheritance, incomplete penetration, variable expression, allelic heterogeneity etc.), nonspecific clinical presentations in children and, last but not least, high costs of genetic examinations. Recent studies have shown that over 50 genes are involved in the onset of DCM. Although 90% of mutations proven in familial DCM have autosomal dominant transmission, only 50% of offspring may have the same mutations. Current genetic testing panels are mostly used in familial cases of DCM and do not focus on more rare mutations. At the same time, children with nonfamilial forms, de novo mutations, or non-genetic forms assumed by DCM are not subjected to routine genetic testing. As a result, families are not subjected to periodic clinical-genetic screening and evaluation. Clinical trial data have shown the phenotype-genotype relationship in some specific forms of DCM, with linked X transmission for example, associated with unfavorable prognosis, including early sudden cardiac death. Genetic counseling and testing should be performed in all children with the DCM phenotype regardless of family history, as well as their family members. The results of genetic testing contribute to the development of a personalized evaluation and treatment program, especially in the prevention of major complications.