Physical inactivity has contributed to rising obesity rates in the United States. Individuals living in lower income communities are less likely than those living in affluent communities to meet physical activity recommendations. Public parks offer a space for residents to participate in physical activity at no cost. This study was conducted to determine whether the public parks in Los Angeles County equally promote physical activity for all park visitors. Over the course of 6 weeks, physical activity was assessed in three Los Angeles public parks each containing different resources and park equipment. A total of 111 and 1186 adult subjects were randomly surveyed and directly observed, respectively. In agreement with previous research, it was found that women and adults with children are less likely to be active (P<0.05). Although the frequency of park visits was positively correlated with the total time spent exercising in a given week for men (P<0.05), a similar correlation was not found for women (P>0.05). In addition, men were more likely to be observed performing vigorous intensity physical activity (P<0.05). Survey results indicated that gender differences in park physical activity behavior are in part due to the proximity between playground equipment and other park resources (P<0.05) and the preference of women to use jogging paths compared to the male preference for sport-specific facilities like basketball courts. The results of this study suggest that the design of public parks in Los Angeles County may not be effective in promoting physical activity for women.