Background: The benefits of physical activity are well established and recognized to prevent adults from many chronic diseases and particularly some forms of cancers. Objectives: The present study was conducted to investigate the present status of physical activity among Saudi adults in Al-Ahsa, and to examine the association between the stages of change for physical activity and perceived barriers, and self efficacy. Methods: A cross-sectional study of 242 subjects (118 males and 124 females) attending health centers aged between 20-56 years, were personally interviewed for demographic data, anthropometric measurement, physical activity level, stages of change for physical activity, self efficacy and perceived barriers. Results: Forty eight percent of the females were overweight and 16.9% of the males were obese with no significant difference between the genders for BMI categories. More than half of the females were inactive and 39% of the males were physically active with a significant difference (P=0.007). Twenty percent of the males were in maintenance stage, while similar percentage of the females were in contemplation stage. However the majority of the subjects were in pre-contemplation stage with a significant difference across the stages. Males had a higher mean score of self efficacy and less external barriers of physical activity. The major barrier among the females was lack of time ($7.2{pm}1.4$) and in the males, lack of motivation ($7.7{pm}1.4$). The females had less internal ($21.2{pm}3.8$) barriers comparable to the males ($23.08{pm}4.7$). Both genders had a significant relationship between stages of changes of physical activity and perceived barriers (internal and external), but in the females no significant difference across the stages was observed for self efficacy unlike the males who had a significant difference for self efficacy and self efficacy categories. Conclusion: The present study provided useful data on stages of change for physical activity and some psychosocial factors (self efficacy and perceived barriers) that can help to tailor strategies aiming at increasing physical activity level according to self efficacy and to the barriers detected, to prevent many chronic diseases including certain types of cancer in Saudi Arabia.