Eighteen subfertile men, with idiopathic normogonadotropic oligozoospermia were treated with an antiestrogenic compound, tamoxifen (Nolvadex), at the dose of 20 mg/day for four months. Hormonal parameters (LH, FSH, Testosterone, Prolactin) were evaluated before treatment and after 45 and 90 days of therapy. Serum LH, FSH and Testosterone increased significantly after 45 days of tamoxifen treatment. Seminal analyses, performed before and after three months of therapy showed improvements in sperm motility and in sperm density. By our clinical findings, tamoxifen can be considered a useful approach for an empiric treatment of idiopathic oligozoospermia.