There are four stages of ovarian cancer. The stage of a cancer describes how much and where the cancer is in the body. It allows us to categorize the gravity of the disease and how best to approach management of our treatment. In the gynecologic cancer world, the stage classifications can be done using two different systems. The International Federation of Gynecology and Obstetrics, the FIGO system, is the more commonly used system by gynecologic oncologists. However, American Joint Committee on Cancer, AJCC criteria, uses a TNM staging system that may be more often used by medical or radiation oncologists. Nonetheless, the rule of thumb is that lower the stage, the more the cancer is contained. Broadly, stage one cancer is contained within one or both ovaries. Stage two is cancer that has spread to the adjacent two or within the pelvis. Stage three is ovarian cancer that has spread to the abdomen, but still only on the surface of various organs. Stage four is ovarian cancer that has spread inside the abdominal organs, like the liver or the spleen or outside the abdominal cavity like the lung.