OBJECTIVES: To assess the prevalence and impact of dyspepsia among Japanese Atrial Fibrillation (AF) patients. METHODS: The 2008, 2009, and 2010 Japan National Health and Wellness Survey (NHWS) datasets were used in this study. The NHWS is an Internet-based survey administered to the adult population in Japan using a random stratified sampling framework to ensure demographic representativeness. Among patients who reported a diagnosis of AF (N=565), those with comorbid dyspepsia were compared with those without dyspepsia on demographics and health history. These groups were also compared on health status (using the SF-12v2), work productivity (using the WPAI), and healthcare resource use (physician visits, emergency room [ER] visits, and hospitalizations) in the past six months using multivariate regression modeling and controlling for baseline differences. RESULTS: Dyspepsia was the most common non cardiovascular comorbidity, affecting over a third (37.4%) of AF patients. This prevalence was higher than in general population (21.3%). Its presence was not associated with any demographic or general health history variables. However, patients with dyspepsia used more AF medications (2.05 vs. 1.54) and had been diagnosed more recently (9.97 vs. 10.58 years). Adjusting for these differences, patients with dyspepsia reported significantly worse physical health status (PCS scores: 41.32 vs. 45.66) and health utilities (0.70 vs. 0.76) (all p<0.05).  Those patients also reported significantly more overall work impairment (29.65% vs. 17.02%) and more physician visits (19.35 vs. 12.62), and ER visits (0.40 vs. 0.14) in the past six months (all p<.05). CONCLUSIONS: Dyspepsia is common among Japanese AF patients. Even after adjusting for confounding variables, dyspepsia was significantly associated with poorer health status, greater work-related impairments, and increased health care resource use. Given the additional burden of this comorbidity, the management of dyspepsia among patients with AF should be a greater area of focus.