Objective: To investigate the molecular etiologic causes of sporadic nonsyndromic hearing loss in Chinese children. Methods: 179 sporadic nonsyndromic hearing loss children were subjected to microarray-based mutation detection for nine hot spot mutations in four of the most common deafness-related genes, including GJB2, SLC26A4, GJB3, and 12s rRNA. Results: The incidence of positive genetic errors was 43.58% with the current set of target genes in sporadic nonsyndromic hearing loss children. Among them, 25.14% of cases had genetic defects in GJB2, 16.76% of cases had pathogenic mutations in SLC26A4, 1.12% of cases were caused by 12s rRNA mutations, and GJB3 mutation was detected in 0.56% of this group of patients. Conclusions: Our results demonstrated that genetic factors were important causes for sporadic nonsyndromic hearing loss in Chinese pediatric cases. Mutations of GJB2 and SLC26A4 are two major genetic causes, whereas mutations of GJB3 and 12s rRNA result in the development of hearing loss in a small percentage of sporadic nonsyndromic hearing loss cases. Microarray testing is a helpful and instrumental screening method in the diagnosis of genetic hearing loss. (C) 2011 Elsevier Ireland Ltd. All rights reserved.