Influence of Socio-demographic Correlates on the Adherence to Physical Activity Recommendations in Adults Aged from 15-to 74 Years. Madrid, Spain Background: To know the adherence to physical activity recommendations of the population is of clinical and social interest. The aim of this study was to estimate the proportion of Spanish adults adhering to the physical activity recommendations, and to examine the influences of socio-demographic correlates. Methods: In the present cross-sectional study we conducted a telephone survey of 1,500 Spanish adults (15-74 years old) from Madrid (Spain). Physical activity (work place, transport and leisure time) was assessed with the version 2 of the Global Physical Activity Questionnaire (GPAQv2). Participants were categorized in three physical activity levels (low, moderate and high). The socio-demographic correlates included: gender, age, educational level, employment status, marital status, smoking status, and self-perceived health. The association between socio-demographic factors and physical activity was examined with multinomial logistic regression analysis. Results: A total of 82% of men and 78% of women (total 80%) had moderate to high levels of physical activity, yet, when considering the leisure time physical activity, only 40,1% of mean and 22,6% of women (total 31.1%) reach the recommendations. Participants with university degree (OR: 2.05; 95%IC: 1.48-2.86), those who were smokers (OR: 1.41; 95%IC: 1.04-1.90), and those who perceived their health as bad (OR: 3.58; 95%IC: 2.39-5.38) were more likely to not to reach the recommendations. In contrast, those participants aged 35-44 years (OR: 0.61; 95%IC: 0.39-0.95) and 45-54 years (OR: 0.52; 95%IC: 0.32-0.83) were less likely not to reach the recommendations. Conclusions: The 20% of adults from Madrid did not reach the physical activity recommendations, and when considering only leisure time physical activity, only 69% reached the recommendations. The findings suggest that the educational level, smoking status, and the self-perceived health seem to be key determinants. There is a large diversity in the physical activity levels in the population subgroup; therefore, there is a need of developing social-ecological approaches to physical activity promotion.