Background: Dilated cardiomyopathy (DCM) is a leading cause of heart failure and cardiac transplantation worldwide. Many cases of DCM are due to genetic or idiopathic etiology. Two prominent contributors to genetic DCM (gDCM) are the TTN and MYH7 genes, which encode proteins associated with DCM etiology. Purpose: This study aimed to synthesize the published literature on the global prevalence of adult and pediatric gDCM within the clinical DCM population and the general population. Methods: A systematic review was conducted by searching MEDLINE® and Embase from database inception to 09/19/2022. We included observational studies reporting the prevalence of gDCM within any population; prevalence of TTN and MYH7 mutations were also extracted. Excluded were studies using family history as a proxy for gDCM. Median with interquartile range (IQR) or mean with standard deviation (SD) weighted by sample size (in cases of calculations with <10 studies) were used to summarize the data. Results: Of 2,720 identified abstracts, 57 studies were included in the review. Among the adult or mixed (adults and children) DCM population in any country, median prevalence was 21.0% for overall DCM-related genetic mutations, 11.4% for TTN mutations, and 3.2% for MYH7 mutations ( Table ). The prevalence of pediatric gDCM within the DCM population was similar (weighted mean: 21.3%). Data on prevalence of gDCM within the general population were scarce. Conclusion: This study highlights the variable prevalence of gDCM reported across different populations and settings. The current evidence may underestimate the genetic causes due to technical limitations in genetic testing and limited screening. Accurately determining the prevalence of gDCM is critical for identifying high-risk populations, developing targeted prevention strategies for disease complications, and improving outcomes; epidemiological studies using long-read sequencing techniques and large cohort datasets with genotype-phenotype correlation analyses are needed.