Summary:Oligozoospermic and asthenozoospermic semen ejaculates, as well as cryopreserved sperm samples prepared by the wash and swim‐up procedure often result in unsatisfactory sperm recovery rates. In this study the glass wool filter and the wash and swim‐up preparation procedures were compared on the basis of their ‘effective’ (number of live sperm per millilitre) recovery rates. The glass wool filter procedure consistantly produced significantly (P= 0.0002) higher viable sperm concentrations, making it the preferred method for the preparation of cryopreserved sperm to be used in assisted reproduction techniques. The use of this preparation procedure has also been shown to have no adverse affect on the fertilizing potential of human spermatozoa in o