A new method is described for the enzymatic preparation of testicular tissue to obtain vital spermatozoa for ICSI. The tissue obtained from both testes by biopsy is studied by means of the semi-thin section method as well as being cryo-preserved. If spermatid formation is assured by semi-thin section histology, vital spermatozoa from the cryo-preserved portion of testicular tissue are enzymatically prepared. In this way it is possible to optimize the reproductive medical treatment for those couples in whom an extracorporal fertilization of oocytes by means of testicular spermatozoa is being considered.