The rapid and accurate diagnosis of pregnancy is a necessity for emergency physicians. Physicians of the 1990s are fortunate to have available inexpensive, rapid pregnancy tests with virtually no false positives or negatives. The current basis of endocrine pregnancy tests is detection of Human Chorionic Gonadotrophin (HCG) in the serum or urine. The single HCG tests in combination with ultrasound, as well as serial HCGs, are also useful in the diagnosis of ectopic pregnancy. Serum progesterone, although at present not widely used in the emergency department, shows great promise as a test useful in the often difficult task of distinguishing ectopic and abnormal pregnancies from viable intrauterine pregnancies.