Objective: To examine the association of multibehavior on multimorbidity. Patients and Methods: Data from the 2005-2006 National Health and Nutrition Examination Survey were used. The study duration was from October 20, 2013, through December 16, 2014. A multimorbidity index variable was created that indicated the number of 14 morbidities that each patient had. A multibehavior index variable was created that indicated the number of 4 health-enhancing behaviors each participant had; physical activity was assessed via accelerometry, dietary behavior was assessed via an interview, smoking was determined via cotinine levels, and sleep duration was self-reported. Results: For the entire sample of 2048 participants, those with 1, 2, 3, and 4 health behaviors, compared with 0 health behaviors, had a 35% (odds ratio [OR], 0.65; 95% CI, 0.47-0.90; P = .01), 44% (OR, 0.56; 95% CI, 0.38-0.82; P = .006), 63% (OR, 0.37; 95% CI, 0.26-0.51; P < .001), and 69% (OR, 0.31; 95% CI, 0.19-0.52; P < .001) reduced odds of being multimorbid, respectively. Only physical activity (beta = -.46) and sleep (beta = -.23) were independently associated with multimorbidity, and only 2 health behavior combinations were associated with multimorbidity: physical activity and sleep (beta = -.17) and physical activity and nonsmoking (beta = -.16). Conclusions: Americans engaging in more health behaviors were less likely to be multimorbid. Physical activity was independently, as well is in combination with other health behaviors, associated with multimorbidity. Implications for developing a multibehavior-multimorbidity framework to treat the patients' holistic needs is discussed. (C) 2015 Mayo Foundation for Medical Education and Research