Seven hundred sixty-seven oxytocin challenge tests (OCT) were performed on 333 high-risk maternity patients. All of the patients had pregnancies complicated by diabetes mellitus, suspected postmaturity, preeclampsia, intrauterine growth retardation, hypertension and other disorders. In conjunction with OCT, 24-hour urinary estriol determinations were performed. Negative OCT's were reassuring for fetal well-being. There were 26 positive OCT's on 24 patients. A positive test was significant in identifying endangered fetuses existing in a markedly unfavorable environment. In our experience, we found the OCT more reliable and more predictable than urinary estriol determination. The oxytocin challenge test proved to be significant in the successful management of these 333 high-risk patients.