Compared with other side effects induced by thalidomide, amenorrhea has been relatively poorly investigated although it was first reported in 1989. The aim of this study was to determine the prevalence of amenorrhea in consecutive women treated with thalidomide in our institution from 1995 to 1999. During that period, 21 women received thalidomide associated with progestin contraception. Their clinical and biological data were retrospectively reviewed. Data concerning their genital life were systematically checked by phone with a simple questionnaire. Transient secondary amenorrhea occurred in 5 women (24%) treated for refractory cutaneous lupus erythematosus (4 cases) or complex aphthosis (1 case). The link between thalidomide and amenorrhea was suggested by the resumption of menses 2 to 3 months after drug withdrawal, recurrence of amenorrhea after reintroduction of thalidomide (1 case) and high serum levels of pituitary gonodotrophins. Amenorrhea secondary to ovarian failure is frequently observed in women treated with thalidomide. Its precise mechanism remains to be elucidated.