Background: The towns and cities where we live form part of our immediate environment, one of a principle determinants of people's health. In Catalonia there are 947 municipalities, however 77,82% of these have only 5,000 inhabitants or less. The comparisons between towns and cities -between small and large municipalities- has been a constant throughout history, but it's important to keep in mind that in recent years, social, economic and technological changes have changed the reality, especially for small municipalities. Knowing how social determinants of health affect the health of inhabitants of different sized municipalities is an opportunity to clarify the differences and reorient policies if necessary. Goals: To determine the degree of association between socioeconomic determinants of health and the well-being of people over 50 in the province of Girona according to the size of the municipality. Methods: A descriptive, transversal and observational study of a population sample of 3,311 inhabitants from 28 municipalities in the province of Girona that participated in the 2013 study: Maturity and Satisfactory Aging in Girona ("MESGI50"). The socioeconomic determinants of health (age, gender, educational level and economic income) and various health status indicators (lifestyle, physical health and emotional well-being) were evaluated using standardized instruments. The relationship between the determinants and the health indicators was analysed using multivariate binary logistics regression models stratified according to the size of the municipalities (less than 1,000 inhabitants, between 1,000 and 5,000, and more than 5,000). Results: The socioeconomic determinants of health were not associated in a uniform way with all the health indicators. Regardless of the size of the municipality gender was mainly associated with obesity and loneliness; age with physical inactivity and self- perceived health; and educational level and economic income with indicators of emotional well-being. Large municipalities presented a greater number of health indicators linked to the determinants of age and economic income. Small and medium municipalities are associated with a lower number of health indicators (19 in both cases) and are distributed more irregularly according to determinants. Conclusions: The effect of socioeconomic determinants on the health of people is confirmed, but the degree of association varies according to the size of the municipalities and the indicator of health that is observed. The specific health differences observed between municipalities of different dimensions suggest a high degree of homogenization of the health of the population