Hearing loss has a genetic etiology in the majority of cases and is very common. The universal newborn hearing screening program, together with remarkable recent progress in the characterization of genes associated with the function of hearing, have resulted in increased demand and exciting possibilities of detecting the molecular basis of hereditary hearing loss through DNA testing. Future molecular diagnostic assays are expected to offer a greater variety of gene-specific tests, as well as combined mutation panels, which will aid in the management of the impressive genetic heterogeneity observed in hereditary hearing loss, especially in individuals with nonsyndromic forms. This review addresses the genetics of hearing loss, discusses the most commonly offered genetic assays for nonsyndromic hearing loss, with advantages and limitations, proposes a practical testing algorithm, and highlights current developments.