The objective is to identify the differences and the main factors influencing health status and well-being variables between institutionalized and non-institutionalized older adults, as well as the interaction effect of institutionalization and age. Data on a total of 468 older adults from a national survey on non-institutionalized and from a study on institutionalized older people were analyzed. Socio-demographic variables and measures on well-being (Personal Well-being Index, PWI), health status (EQ-5D), functional ability (Barthel Index), depression (Hospital Anxiety and Depression Scale-Depression subscale), loneliness and comorbidity were used. Analysis of variance and Kruskal-Wallis tests to examine differences between groups and multiple regression analyses to identify factors associated to health and well-being were performed. Significant differences in health status variables, but not in well-being were detected between groups. Controlling for age, differences in health status (EQ-VAS) were found to be not significant in both groups. In the non-institutionalized group, people aged 78 years or more reported a significantly lower well-being (PWI) than younger counterparts. Step-wise multiple regression analysis showed that depression, functional dependence, loneliness and sex were associated with health status; while depression, health status, loneliness and the interaction of age-institutionalization were related to well-being. The results suggest that age influences community-dwelling older adults' well-being to a greater extent than it does to institutionalized older people. This finding has implications for resource allocation and interventions addressed to improve health and well-being in older adults.