Objective To summarize the prevalence,risk factors,and characteristics of testicular adrenal rest tumors(TART) in children and adolescent males with congenital adrenal hyperplasia(CAH) due to 21-hydroxylase deficiency (21-OHD).Methods During past 4 years,there were 44 males with CAH caused by 21-OHD undergone testicular ultrasound scan in our clinic.We have diagnosed 13 cases of TART and summarized the characterizations.Results The prevalence of TART in our group was 29.5％ with 11 cases of salt wasters and 2 cases of simple virilizers.The median age of TART diagnosis was 10.2 years.The median follow-up period of TART was 3.0 years.History of poor control of CAH was found in every case before diagnosis of TART.The doses of hydrocortisone were increased in 5 cases of TART who refused operations or had small TART,resulting in tumor regression in two of those five patients.Testis-sparing surgeries were performed in 8 patients with symptoms relieved; 7 of those eight patients presented elevated FSH and LH after operations.Conclusions Prevalence of TART in our CAH children and adolescent males was 29.5％.Testicular ultrasound was useful in TART screening.TART should be considered when a CAH patient with poor control,especially in post-pubertal one.Delayed management of TART may lead to impaired testicular function.Increased doses of glucocorticoid may be effective in TART of small size.Testis-sparing surgery should be also considered if necessary.