11603 Background: Fatigue is one of the most common and distressing symptoms reported by patients with gynecological cancers, but few studies have empirically examined whether it resolves without intervention. The aims of this study were to identify: 1) clinically-distinct subgroups of patients with fatigue over time and 2) medical and psychological predictors of clinically-significant fatigue one-year post-diagnosis. Methods: Secondary analysis of a prospective cohort study. Symptoms of fatigue, depression, and anxiety were assessed at diagnosis, 6-months, and 12-months with the 10-item Fatigue Assessment Scale (FAS), and the Hospital Anxiety and Depression Scale (HADS), respectively. Group-based trajectory modeling was used to classify patients by their fatigue scores over time, and logistic regression models were fit to examine associations between clinically-significant fatigue and demographic, clinical, and psychosocial characteristics. Patients with recurrent or primary progressive cancers were excluded from the primary analysis. Results: Among 312 participants with newly diagnosed ovarian (n = 112) or endometrial (n = 200) cancers, the median age was 66 years (IQR = 60-72 years), 36% had ovarian cancer, and 79% had early stage disease. At baseline, 49% reported clinically significant fatigue and one year later, 42% had persistent fatigue. During the year after diagnosis, there were three distinct trajectories of fatigue that persisted: (1) severe fatigue (15%), (2) moderate fatigue (45%), and (3) no fatigue (41%). Patients with ≥2 comorbid conditions (odds ratio [OR] 2.52, 95% confidence interval [CI] = 1.21-5.27, P = 0.01), clinically significant fatigue at baseline (OR 5.47, 95% CI = 2.71-11.03, P < .0001), and those reporting depressive symptoms at baseline (OR 3.45, 95% CI = 1.13-10.55, P = 0.03) were more likely to report clinically-significant fatigue at 12 months. Conclusions: Half of women with gynecologic cancers have clinically-significant fatigue at diagnosis and 42% of survivors have persistent fatigue one year later, suggesting spontaneous regression of symptoms is rare. Importantly, depressive symptoms contribute to persistent fatigue and are modifiable with psychological interventions. Future studies should test scalable psychological interventions to address depressive symptoms, reduce fatigue, and improve quality of life in women with gynecologic cancers.