The level of reproductive hormone analyis with Cryptorchidism boys Backgrounds: The prevalence of Cryptorchidism is 1-5% of among pediatric abnormalities. Cryptorchidism is congenital abnormality in which one or two testis can be found in inguinal and abdominal cavities (Undescended testis). According to they last year statistics; 10% of annual visits to surgical cabinet and 22% of impatient in surgical department were children with cryptorchidism. Study objective: To identify risk factors and level of reproductive hormones. Materials and method: The case control study which was done. Cases were 81 cases with cryptorchidism aged 4-18 years. Controls 77 healthy children visited to adolescent cabinet. Results: Median age of children at the time of surgery 92.64 year. The 66.7% children had orchidopexy in between ages of 5-15 years. Hormone profiles had should no significant difference between cases and controls of children aged 11 years. But, there was significant difference were found in FSH and testosterone levels older than 11 years old. It meanest higher FSH-(2.40.14U/l) (p=0.018), and lower testosterone-4.80.22nmol/l (p=0.09) level in children with cryptorchidism. Correliation analysis had should that possible risk factors for cryptorchidism are premature births (23.7%), severe gestose (72.8%), pregnancy associated medical condition(46.9%). There was no significant difference of hormone levels in children with inguinal and abdominal cryptorchidism. Conclusion: On the basis of above study, it is recommended that early screening and early correction before 2 years will prevent from further atrofic changes of testis. It is also recommended that reproductive hormone level screening more useful for the children older than 11 years old.