Ectopic pregnancy is a high-risk diagnosis that is increasing in frequency and is still commonly missed in the emergency department. The emergency physician needs a high index of suspicion and must understand that the history, physical examination, and a single quantitative beta-hCG level cannot reliably rule out an ectopic pregnancy. Most pregnant patients who present to the emergency department during the first trimester with abdominal or pelvic pain, regardless of the presence of vaginal bleeding, should undergo further evaluation with ultrasonography. Ultrasound findings in conjunction with quantitative beta-hCG levels guide the management of the patient.