We investigated the prevalence of physical inactivity and associated factors among the adult population in Joaçaba, Santa Catarina, Brazil, using a cross-sectional, population-based model with subjects from 20 to 59 years of age (n = 579). The short version of the International Physical Activity Questionnaire (IPAQ) was used to define the level of physical activity. Descriptive crude analyses and Poisson regression were performed to test the associated variables. The response rate was 99.6%, and prevalence of physical inactivity was 57.4% (95%CI: 53.4-61.4). Physical inactivity was associated with not working or not being retired, income (> U$500/month), age > 30, body mass index above or below standard, and self-reported difficulty with mobility, regardless of gender. The physical inactivity level was lower than in other population-based Brazilian studies. The results may help promote regular physical activity through appropriate public policies.