Accumulating 30 minutes or more of moderate-intensity physical activity a day is considered a marginal amount of physical activity for weight control (CDC, 1995; Bair et al, 2004). This study's purpose was to identify predictors of physical activity frequency as a weight control strategy. A part of the data from the 2005 Behavioral Risk Factor Surveillance System study was used for this study. Study participants were from seven states (N = 51,996), and 70.7% were participants in moderate and/or vigorous-intensity physical activity for 30 minutes or more at least once a week and 29.3% were not. The dependant variable was physical activity frequency (i.e., how many days a week), and the independent variables of interest were intention to control weight, a professional's advise on weight control, using diet for weight control, using physical activity for weight control, and body mass index. Since the physical activity frequency is a count outcome and its distribution is highly positively skewed and over-dispersed, and we assume that there is always-zero group (i.e., sedentary people), a zero-inflated negative binomial regression model was fitted using Stata 9.2. The results consisted of two different equations: a binary equation to predict whether people do not participate in physical activity at least once a week; a count equation to predict physical activity frequency. Statistically significant predictors of binary equation were intention to lose weight (b = .40, p<.001), intention to maintain weight (b = .31, p<.001), using physical activity for weight control (b = -1.24, p<.001), and BMI (b = .03, p<.001). Statistically significant predictors of count equation were intention to lose weight (b = -.19 p<.001), intention to maintain weight (b = -.16, p<.001), using physical activity for weight control (b = .26, p<.001), and BMI (b = -.01, p<.001). Using diet for weight control and a professional's advice to control weight were not significant in either equation. The results suggest that people who have an intention to control weight tend to be less physically active, those who use physical activity for weight control tend to be more physically active, and heavier people tend to be less physically active. Further study is needed to determine the cause-effect relationship among the variables, and the effectiveness of a professional's advice as a physical activity intervention strategy.Keyword(s): exercise/fitness/physical activity, nutrition, obesity issues