The rising prevalence of overweight throughout the world has prompted the recognition of a "global epidemic," with increases being partially attributed to population-level reductions in physical activity and increases in sedentary behaviors. In China, overweight has started to emerge as a significant public health concern. Prospective research on the relationship between physical activity and overweight is relatively uncommon in the developing world, and China offers a unique opportunity for study given the tremendous increases in urbanization and economic development seen in the recent past. Such growth can impact the physical activity patterns of individuals by driving concomitant increases in car ownership, in labor-saving household devices, in the mechanization of the workplace, as well as decreases in the proportion of the workforce employed in more physically-demanding occupations. The purpose of this research was to examine the impact of urbanization on the physical activity patterns of Chinese adults, as well as to investigate the impact of these changes on weight status. Analyses were conducted using data from the China Health and Nutrition Survey, an ongoing longitudinal study of a socioeconomically and demographically diverse sample of the Chinese population. Using multilevel models we showed that community-level urbanization was importantly associated with occupational activity after adjustment for individual-level sociodemographic factors. In subsequent analyses we found both occupational and household activity to be important predictors of weight in men and iv women, while leisure time and transportation activity did not have the same effect. This research helps to fill an important gap in understanding the impact of urbanization on physical activity and on subsequent overweight in an enormous transitioning populace.