OBJECTIVE We evaluated the safety and efficacy of percutaneous sperm aspiration from the epididymis or testicle as a diagnostic technique to confirm sperm production and as a therapeutic technique to harvest sperm for use in intracytoplasmic sperm injection. METHODS We present our experience with 69 sperm aspiration procedures in men considered to have nonreconstructible obstructive azoospermia. This short outpatient procedure was performed using a butterfly needle with the patient under intravenous sedation and local anesthesia. RESULTS Of the 32 diagnostic aspirations 20 demonstrated mature and motile sperm, 9 maturation arrest and 3 germ cell aplasia. In 35 of 37 therapeutic sperm aspirations (95%) adequate samples of sperm after processing (mean of 5.4 million) were obtained. Of 24 epididymal aspirations 13 (54%) had sufficient residual sperm for cryopreservation of 1 to 5 vials (mean 2.5) containing an average of 170,000 sperm per vial. In the 32 intracytoplasmic sperm injection cycles 221 of 392 eggs (56.3%) fertilized (2PN) and 6 resulted in ongoing pregnancies (21.4% per transfer). There have been no acute or chronic complications in this patient population. Ten men underwent a second successful aspiration procedure for intracytoplasmic sperm injection and 3 underwent a third aspiration without added difficulty. CONCLUSIONS Percutaneous epididymal or testis sperm aspiration is a minimally invasive sperm retrieval technique and appears to be an effective alternative to microsurgical epididymal sperm aspiration, which is more invasive, costly and technically difficult.