Intracytoplasmic sperm injection (ICSI) with in vitro fertilization represents one of the most significant advances in fertility technology. In this relatively new procedure, a single viable sperm is microinjected into an oocyte that has been extracted transvaginally. After fertilization occurs, the embryo is transferred into the uterus. This procedure now affords men who were previously thought to be irreversibly infertile the chance to initiate their own biologic pregnancy. However, because of the procedure's significant costs and its potential risk to the mother, careful selection of couples following a thorough male factor evaluation is mandatory.