Ovarian cancer is the deadliest of gynecologic cancers. In recent years, several studies have produced a new understanding of the tumor biology of ovarian cancer. Therefore, FIGO and the WHO classifications were revised. Both classifications are essential criteria for the treatment decision. We sought 1) to compare the major changes between the both classifications; 2) to examine the effects on the therapeutic and prognosis of the Ovarian, Fallopian Tubes and Peritoneum cancer in our sample. We performed a case series observational descriptive study of 210 patients who have been diagnosed with and/or treated for a malignant ovarian tumor at University Clinic Hospital of Salamanca from 2010-2016. For inclusion, subjects were required to be admitted, have, at least, one hospital admission or major ambulatory surgery related to the diagnosis and/or treatment of ovarian cancer. According to the new FIGO subdivision of stage IC, we obtained 2,52% in substage IC2. Stage II tumors represent less than 10 % in both FIGO classifications in our sample. The vast majority of ovarian cancer cases are in III FIGO stage. We have found 6,72% on stage IVA and 16,81% on stage IVB. In the new WHO classification, in addition to the different nomenclature, the main change to the Serous group was the increase in the HGSC percentage. In the previous classification we had 6,48% of endometrioid malignant tumor and in the new classification this rate has decreased to 2,78%. Previously we had transitional cell tumors (0,93%) and unclassifiable tumors (10,19%) but these groups have been erased. Concerning Serous tumors, the separating line between adenomas and borderline tumors (SBOT) has been refined in the current WHO classification. In our study, the HGSC has reached 55,56% in the new WHO classification thanks to the incorporation of serous malignant adenocarcinoma (1988 WHO classification). We found 1,85% of Seromucinous Borderline Tumors (0,93% from endocervical MBOT and the other 0,93% from mixed epithelial Borderline tumors). We found that 4,2% of the previous Stage IIIC patients have changed to stage IIIA2 or stage IIIB and this group of patients has a better prognosis and a superior survival rate. This study demonstrated that the new-created WHO and FIGO classifications have improved the ability to predict the prognosis and consequently to change the therapeutic managements in Ovarian cancer patients.