OBJECTIVE To study the histological changes of uterine cervix during termination of early pregnancy by mifepristone and prostaglandins (PG). METHODS A total of 24 women who requested medical abortion was recruited. For each woman, 3 cervical biopsies were taken: before mifepristone treatment; 48 hours after mifepristone 150 mg single dose treatment (i.e. immediately before PG administration); and 1 hour after gestational sac expulsion. Specimens were studied by optical and electron microscopy. RESULTS Significant collagenolysis as demonstrated by marked reduction and irregularity of collagen fibers, abundant accumulation of an amorphorous material of ground substance, and infiltration of neutrophilic polymorphonuclear leukocytes were shown in stroma as well as in the deep portion of cervix after mifepristone as compared to the samples of early pregnant cervix before treatment. These changes presented to a further extent after the expulsion of gestational sac. CONCLUSIONS The changes observed were similar to previous reports during cervical dilatation in term delivery. The present study confirmed the histological cervical ripening effect by mifepristone and suggested it may be used as cervical ripening agent before induction of labor as well.