IF THE vaginal smear could be employed as an accurate diagnostic and prognostic aid in abortion, our management of the accidents of early pregnancy might be greatly simplified. It is well known that every obstetrician-gynecologist is dissatisfied with a purely clinical approach to the problem of abortion. It is often difficult to decide whether a patient is pregnant or not. If she is gravid and bleeding, the case may be one of abortion yet it may not necessarily mean that the pregnancy is terminated. Abortion, of course, may be threatened, incomplete, complete or missed, and either uterine or tubal. We have evaluated 724 stained vaginal smears in 201 cases of questionable or abnormal early pregnancy. Seventy-five of these cases were instances of spontaneous abortion. This report will present the characteristic vaginal smear changes in early pregnancy and abortion together with certain practical and implied values of this laboratory procedure.