Recent advances in ultrasound diagnosis and the high sensitivity of modern urinary pregnancy tests have enabled the diagnosis of many cases of small tubal ectopic pregnancies that were undetectable in the past. Many of these pregnancies represent early tubal ectopic pregnancies or tubal miscarriages that are eligible for non-surgical treatment, such as medical treatment and expectant management. Medical treatment is mainly focused on systemic methotrexate, which is the most commonly used drug in clinical practice. Methotrexate facilitates non-invasive outpatient management of ectopic pregnancy. Systemic methotrexate and expectant management are used only in women with a low risk of complications, such as a small ectopic pregnancy, low serum human chorionic gonadotrophin (hCG) concentration and no signs of intra-abdominal bleeding. However, these women remain at risk of tubal rupture. Serum hCG monitoring is therefore mandatory to detect impending treatment failure and inadequately declining serum hCG concentrations. Additional methotrexate injections or surgical intervention may then be needed. This chapter provides an overview of the best available evidence on the conservative management of tubal ectopic pregnancy, both medical treatment with systemic methotrexate and expectant management. Systemic methotrexate, Methotrexate is a folic acid antagonist that inhibits de novo synthesis of purines and pyrimidines, thereby interfering with DNA synthesis and cell proliferation. Secondary to its effect on highly proliferative tissues such as trophoblast, methotrexate has a strong dose-related potential for toxicity. Adverse effects of systemic methotrexate include stomatitis, conjunctivitis, gastritis-enteritis, impaired liver function, bone marrow depression and photosensitivity.