Abstract Background: Fatigue, sleep dysfunction, and joint symptoms may negatively impact quality of life in breast cancer survivors (BCS). Prior studies examining associated factors have yielded inconsistent results. Objective: Determine demographic, medical, exercise-related, body composition and serum inflammatory factors associated with fatigue, sleep dysfunction, and/or joint symptoms in BCS. Methods: Post-hoc analysis of baseline data completed by 37 BCS enrolled in a pre/post intervention study or randomized trial. Self administered survey assessed demographics, medical variables, self-efficacy (i.e., confidence in ability to exercise), fatigue (FSI), sleep dysfunction (PSQI), and joint symptoms (WOMAC). Sleep was also objectively assessed with an accelerometer. Body composition was assessed by body mass index (BMI), waist-to-hip ratio (WHR), and percent body fat (bioelectrical impedance). Cardio respiratory fitness was assessed with sub maximal treadmill test and muscle strength with back/leg extensor dynamometer. Multiplex high sensitivity assay or ELISA was performed on fasting serum samples to determine levels of cytokines or other markers related to body composition. Due to the skewed nature of several variables, Spearman correlations (r) were performed. A significant p value was set at <.05. Results: Participant mean age and education were 55 ± 10.1 and 15 ± 2.8 years, respectively. The majority (87%) were of European heritage with breast cancer stage distribution being I (51%), II (38%) or III (11%). Daily amount of fatigue was significantly associated with months since chemotherapy (r=.43, p = .027), number of comorbidities (r = .33, p = .0497), and fitness (r = -.35, p = .033). Depending on the subscale, self reported sleep dysfunction was associated with income (r = -.36, p = .029), number of comorbidities (r = .37, p = .028), WHR (r = .45, p = .005), tumor necrosis factor (TNF) α (r = .36, p = .029), interleukin (IL)-8 (r = -.45, p = .006), IL-10 (r = -.42, p = .011), TNF α /IL-10 ratio (r = .54, p = <.001), insulin (r = .48, p = .003), and adiponectin (r = -.36, p = .031). Time awake while in bed (accelerometer) was significantly associated with race (r = -.39, p = .019), muscle strength (r = -.35, p = .034), fitness (r = -.48, p = .003), adiponectin (r = -.39, p = .020), and monocytic chemotactic protein (MCP)-1 (r = -.33, p = .047). Time asleep was associated with race (r = .36, p = .031) and leptin (r = -.36, p = .031). Joint symptoms were significantly associated with age (r = .43, p = .008), education (r = -.34, p = .041), number of comorbidities (r = .60, p = <.001), self-efficacy (r = -.55, p = .003) and BMI (r = .33, p = .048). Conclusion: Fatigue and sleep dysfunction were significantly associated with medical factors and fitness. Sleep dysfunction was also associated with demographics, inflammation, strength, and body composition. Joint symptoms were associated with demographics, medical factors, self-efficacy and BMI. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1830. doi:10.1158/1538-7445.AM2011-1830