e23248 Background: Sleep disturbance and fatigue are prevalent among advanced ovarian cancer (OC) patients and are associated with poor health outcomes. It is unclear how sleep disturbance and fatigue vary across treatment timelines. This study evaluated how patients rate their sleep disturbance and fatigue levels at different points in their treatment trajectory. Methods: 200 U.S. patients with stage III/IV OC diagnosed in 2020-2023 were enrolled. Survey items asked patients to retrospectively assess their sleep disturbance and fatigue levels prior to diagnosis, during treatment, and presently. Sleep disturbance and fatigue were measured using a custom set of Patient-Reported Outcomes Measurement Information System (PROMIS) items based on previous findings. Most were receiving maintenance therapy (44%) or other treatments (34%), and 23% completed treatment. Nearly all participants received surgery (93%) and chemotherapy (97%). 44% of patients had received PARP inhibitor (PARPi) therapy, 18% received immunotherapy, and < 10% received other therapies. Repeated sample t-tests compared symptom burdens. Results: Participants ranked sleep disturbance as most intense during chemotherapy (52%), followed by surgery (33%), hormone therapy (32%), and PARPi (15%). Most participants ranked fatigue as most intense during chemotherapy (67%), followed by hormone therapy (31%), surgery (20%), and PARPi therapy (17%). Paired t-tests show that among participants who received only surgery, chemotherapy and PARPi therapy, sleep disturbance was perceived to be significantly more intense during chemotherapy than when receiving PARPi, t(55) = -2.83, p = .006) and in the 2 weeks after surgery than PARPi therapy, (t(55) = -2.08, p = .043) ( Table). Fatigue was significantly more intense during chemotherapy than when receiving PARPi, (t(55) = -6.21, p < .001) and following surgery than PARPi (t(54) = -4.16, p < .001). Conclusions: OC patients experience intense sleep disturbance and fatigue and perceive levels differently depending on treatment. Chemotherapy was rated the worst for both sleep disturbance and fatigue compared to PARPi and other therapies. Targeted screening and psychosocial support can address these symptoms throughout treatment, especially after chemotherapy. [Table: see text]