Selection of antibody-free spermatozoa by immunobead adsorption was performed as a preliminary test in order to check probable recovery before introducing the procedure in an in-vitro fertilization (IVF) trial. On this basis, only nine out of 21 couples could be allocated to the study on IVF, which was designed to compare fertilization rates obtained with the immuno-selected spermatozoa fraction versus the control swim-up fraction. The study comprised eight properly controlled IVF procedures with sibling oocytes. Despite the high severity of antibody-binding in the fresh semen [mean of 91% for immunoglobulin (Ig) G, 77% for IgA], selection of antibody-free spermatozoa was successful in seven out of eight cases (mean of 15% for IgG, 20% for IgA). Nevertheless, mean fertilization rate on a per patient basis was not different after using one of the two sperm preparation procedures. Four patients had similar fertilization rates with the two sperm fractions, while for three patients fertilization was achieved only with the immuno-depleted fraction. In terms of embryo quality, similar results between the two groups were obtained. Two pregnancies were obtained, one was obtained with swim-up-prepared spermatozoa alone; the second, a twin pregnancy, originated from both the swim-up and immuno-depleted sperm populations. From this study, it can be concluded that the technique of immunobead adsorption itself seems attractive for the selection of antibody-free spermatozoa, but can be applied only to a limited population of patients (< 50%) suffering from immunological male infertility. Furthermore, in cases where immunodepletion seemed successful, no consistent benefit was observed in terms of IVF performance.(ABSTRACT TRUNCATED AT 250 WORDS)