Context: We investigated the efficacy and safety of two different treatments that have not been evaluated in peripuberty boys with hypogonadotropic hypogonadism (HH). Objective: The objective of the study was to assess the effectiveness and safety of GnRH or human chorionic gonadotropin (hCG) treatment in adolescent boys with HH. Design: Twelve patients received 8-10 mu g of GnRH, sc injected every 90 minutes using a pump. Another 22 patients received hCG, injected im as follows: for the first 3 months, 1000 IU of hCG was injected two times per week and then once every other day for the next 3 months. The dose of hCG was increased to 2000 IU after a 6-month treatment and the above cycle was repeated for another 6 months. All patients were treated for 12-14 months and followed up every 3 months. Setting: Thirty-five participants were chosen from Beijing Children's Hospital from 2008 to 2014. Twenty-three patients with Kallmann syndrome and 12 with normosmic idiopathic hypogonadotropic hypogonadism. The age ranged from 10 to 16 years. Intervention(s): Twelve patients were treated with pulsatile pump GnRH (group 1), and 22 patients were treated with im hCG (group 2). One patient was treated successively with hCG and GnRH, which was removed in data analysis. Main Outcome Measure(s): Testicular volume was measured by an orchidometer. The levels of T, LH, and FSH serum were measured with a chemiluminesent immunoassay. Bone age was measured by x-ray. Results: Patients treated with GnRH showed larger testes than those treated with hCG. Patients in both groups showed a significantly increased length of penis and T levels. But the difference of the two groups was not statistically significant. There was no significant difference in side effects in both groups. Conclusions: Boys with HH may be effectively treated with GnRH. We suggested that GnRH exhibits higher efficacy in treating adolescent boys with HH than hCG.