The prognostic significance of peritoneal washing cytology in gynecologic neoplasms is controversial. The presence of neoplastic cells in peritoneal washings is currently part of the Federation of Gynecology and Obstetrics and American Joint Committee on Cancer TNM staging systems in cases of ovarian and fallopian tube neoplasms without metastasis beyond the pelvis. In this study, we retrospectively reviewed all cases of ovarian and fallopian tube neoplasms in which cytologic studies were performed. The utility of cytology in tumor staging and the relationship between cytology results and patient outcome are studied. All cases of ovarian and fallopian tube neoplasms in our institution between July 2002 and July 2012 were reviewed. Primary tumor characteristics including type and pelvic extension were collected, categorized, and correlated with peritoneal washing cytology. Final tumor staging was reviewed and the impact of positive cytology was evaluated. A total of 120 cases of ovarian and fallopian tube neoplasms without extrapelvic metastasis were identified within the study period. Peritoneal washing cytology was positive in 24% (29/120) of neoplasms and upstaged the tumor 83% (24/29) of the time when positive. Overall, 20% (24/120) of reviewed cases were upstaged based on positive cytology results. Peritoneal washing cytology remains a useful staging tool for ovarian and fallopian tube neoplasms limited to the pelvic cavity. Positive cytology results in upstaging in a significant proportion of the cases regardless of the tumor type. A larger study is needed to analyze follow-up data to determine if upstaging based on positive cytology adversely affects outcome.