Microsurgical epididymal sperm aspiration (MESA) combined with intracytoplasmic sperm injection (ICSI) represents a great advance in the therapy of non-reconstructable obstructive azoospermia. For procedure synchronization, a great number of organizational facilities are needed. Intentional cryopreservation of the aspirate may reduce these problems, therefore the aim of this study was to analyse the amount and quality of aspirate fluid obtained by means of MESA and the quality of the vials after thawing. Furthermore, the available cryopreserved straws were calculated. A total of 93 consecutive MESA procedures were performed and epididymal spermatozoa were obtained in 88 patients. Mean sperm concentration was 40.9 x 10(6) spermatozoa/ml. Global and progressive motility were 24.8 and 7.5% respectively. In one-third of the aspirates, no progressive motile spermatozoa were found. The mean number of straws available was 7.6. In 33 ICSI cycles with frozen-thawed epididymal spermatozoa, a pregnancy rate of 42.4% was achieved. In conclusion, these data show that enough spermatozoa are available for various ICSI cycles following a single MESA procedure in men with non-reconstructable obstructive azoospermia. Furthermore, ICSI with cryopreserved spermatozoa leads to excellent pregnancy rates