Pregnancy of unknown location (PUL) is a descriptive term for when a woman with a positive pregnancy test has a transvaginal ultrasound that cannot determine the site of the pregnancy. While the majority of women with PUL are subsequently diagnosed with a spontaneous abortion or viable intrauterine pregnancy, 7% to 20% of these women have an ectopic pregnancy. The potential for morbidity and mortality related to an ectopic pregnancy means that considerable care is necessary in the evaluation and management of women with PUL. In some cases, the location of the pregnancy is never determined and the PUL is categorized as resolving or persisting. Evidence suggests expectant management is a safe and effective approach for most women with PUL and should be the mainstay of care. However, in the case of persisting PUL, continued concern for ectopic pregnancy remains. Strategies for deciding when to intervene when a woman has a PUL are reviewed. A variety of clinical tools, including serum beta human chorionic gonadotropin (β-hCG), repeat ultrasonography, dilation and curettage (D&C), and empiric methotrexate therapy are discussed. Finally, a proposal is made that women with persisting PUL can be presented with the option of choosing expectant management, diagnostic D&C, or empiric methotrexate treatment.