Although infertility of hypogonadotrophic aetiology is uncommon (0.5-1%), it is important as a potentially treatable cause of male infertility. Broadly, hypogonadotrophic hypogonadism (HH) is divided into two categories, idiopathic and secondary postpubertal. In order to determine whether gonadotrophin replacement is sufficient to treat hypogonadotrophic infertile men or there is a substantial need for intracytoplasmic sperm injection to increase chances of pregnancy, we performed a retrospective clinical analysis of seventeen hypogonadotrophic adult men (aged 25-38). Five patients had orchiopexy for cryptorchidism; three prepubertal and two postpubertal. All had non-obstructive azoospermia and received a combination of human chorionic gonadotrophin (hCG) and follicle stimulating hormone (FSH) for 4-24 months. Viable sperms started to appear in the ejaculate 3 months after treatment. Natural conception was achieved in six men with secondary HH (developed after head trauma, infection and surgery). By contrast, intracytoplasmic sperm injection (ICSI) was needed to produce successful fertilisation in the eleven men with idiopathic HH after failed gonadotrophin treatment. In conclusion, we recommend that ICSI should be considered, in addition to gonadotrophins to enhance the fertility of men with IHH, once oligospermic.