Objectives: To investigate levels of moderate-to-vigorous physical activity (MVPA) in a large sample of persons with multiple sclerosis (MS) and controls using accelerometry as a measure of physical activity, and to compare the rates of meeting public health guidelines for MVPA (ie, 30min/d) between persons with MS and controls. Design: Secondary analysis of a combined data set of persons with MS and healthy controls from 13 previous investigations of physical activity over a 8-year period (2005-2013). Setting: University. Participants: Participants with MS (n = 800) were recruited primarily within Illinois through multiple sources, including print and e-mail flyers and an online advertisement on the National Multiple Sclerosis Society website. Healthy controls (n = 137) were recruited via public e-mail postings delivered across the university community. Interventions: Not applicable. Main Outcome Measures: Levels of MVPA and meeting public health guidelines for MVPA between persons with MS and controls. Results: After controlling for covariates (ie, age, sex, education, race, income), there was a moderate (d = .68) and statistically significant (F = 47.2, P<.001) difference of 13.1 minutes of MVPA per day (95% confidence interval, 9.4-16.8) between MS and controls. There was a difference in the rates of meeting public health guidelines for MVPA (x(2)=50.7, P<.001) between MS patients (20%) and controls (47%). Among those with MS, minutes of MVPA significantly differed as a function of education, employment status, clinical course, disease duration, and disability status. Conclusions: We provide data using an objective physical activity measure and a large sample to indicate that only a small proportion of persons with MS are achieving adequate amounts of daily MVPA. (C) 2013 by the American Congress of Rehabilitation Medicine