ABSTRACT Purpose: The purpose of this study was to examine the relationship between self-reported sedentary time (ST) and the cumulative risk of preserved ejection fraction heart failure (HFpEF) and reduced ejection fraction heart failure (HFrEF) using a diverse cohort of U.S. adults 45-84 years of age. Methods: Using data from the Multi-Ethnic Study of Atherosclerosis (MESA), we identified 6,814 subjects (52.9% female). All were free of baseline cardiovascular disease. Cox regression was used to calculate the hazard ratios (HR) associated with baseline ST and risk of overall heart failure (HF), HFpEF, and HFrEF. Weekly self-reported ST was dichotomized based on the 75th percentile (1,890 min/wk). Results: During an average of 11.2 years of follow-up there were 178 first incident HF diagnoses; 74 HFpEF, 69 HFrEF and 35 with unknown EF. Baseline ST >1,890 min/wk was significantly associated with an increased risk of HFpEF (HR [95% CI]; 1.87 [1.13 – 3.09], p= 0.01), but not HFrEF (HR [95% CI]; 1.30 [0.78 – 2.15], p= 0.32). The relationship with HFpEF remained significant in separate fully adjusted models including either waist circumference (HR [95% CI]; 2.16 [1.23 – 3.78], p < 0.01) or body mass index (HR [95% CI]; 2.17 [1.24 – 3.80], p < 0.01). Additionally, every 60 minute increase in weekly ST was associated with a significant 3% increased risk of HFpEF (HR [95% CI]; 1.03 [1.01 – 1.05], p < 0.01). Conclusions: Sedentary time > 1,890 min/wk (~4.5 h/d) is a significant independent predictor of HFpEF, but not HFrEF.