OBJECTIVE To determine the mode of inheritance of familial nonsyndromic Mondini dysplasia. METHODS Correlative clinical genetic analysis of a single kindred. METHODS Clinical history, physical examination, audiologic analysis, computed tomography of the temporal bones, and cytogenetic analysis. RESULTS The male proband, three affected sisters, and an affected brother are offspring of unaffected parents. The mother and an unaffected brother have audiologic findings suggestive of heterozygous carrier status for a recessive hearing loss gene. CONCLUSIONS Pedigree analysis indicates autosomal recessive inheritance in this family. The observed inheritance and clinical, audiologic, and radiologic findings are different from those previously described for another family with nonsyndromic Mondini dysplasia. The phenotype in this study family therefore represents a distinct subtype, indicating clinical and genetic heterogeneity of this disorder. This information should facilitate future molecular linkage analyses and genetic counselling of patients with inner ear malformations.