Medical students (MS) reporting higher physical activity (PA) levels are more likely to deliver preventive counseling to their patients. Limited data is available regarding behavioral factors associated with MS meeting moderate and vigorous PA recommendations (MVPAR). PURPOSE: To evaluate sociodemographic factors, healthy personal habits (HPH) and perceived barriers associated with MS meeting MVPAR. METHODS: A cross-sectional survey (web-based, culturally-adapted Spanish version of the "Healthy doc=Healthy patient" survey) was conducted in Colombian MS from 24 schools (1st year n=1322; 5th year n=844) during 2007 (response rate= 74.6%). The main outcome was meeting or not with the MVPAR (>150min/week). Sociodemographic factors, HPH and barriers perception were assessed through logistic regressions for the whole population, gender and school year. RESULTS: In general the associated variables with meeting MVPAR were: male sex and eating more than 5 fruits and vegetables /day (OR 1.5, p<0.001; OR 1.6, p<0.001). Lack of skills was a significant barrier for meeting MVPAR (OR 0.7, p=0.002). MS who agreed with "My medical school's curriculum emphasizes preventive medicine" and "I will be able to provide more credible and effective counseling if I exercise" were more likely to meet MVPAR (OR 1.4, p=0.01; OR 1.4, p=0.02). First year female students (FS) from very low socioeconomic status were less likely to meet MVPAR (OR 0.5, p=0.02). FS were less likely to meet MVPAR when they reported the barriers no social support (OR 0.5, p<0.001) and fear to get injured (OR 0.3, p=0.002) in first year and lack of skills (OR 0.4, p=0.001) in fifth year. Usual perceived barriers as lack of time, limited access/budget and lack of energy were not significantly associated with medical students' compliment with MVPAR regardless of their gender and school year. First year FS were more likely to meet MVPAR if they agreed that their classmates promoted HPH (OR 2.8, p=0.005). Similarly, fifth year FS were more likely to meet MVPAR if they perceived their faculty as good role models (OR 2.4, p=0.03). CONCLUSIONS: We found significant perceived barriers and school-related factors associated with MS meeting MVPAR. These results should help designing intervention strategies to promote PA among MS.