THE need for capacitation of rabbit sperm has been well documented1–3, but the requirements for the production of this phenomenon are still unclear. Capacitation has not been achieved in vitro in a defined media, and partial Capacitation occurs in uterine fluid and beta-amylase solutions4. Incubation of sperm suspensions in a double ligated and distended uterine horn delays capacitation without altering the fertilizing ability of sperm5.