Background: The population of actively working older people is growing rapidly. The relationship between quality of life, levels of physical activity and functionality in this population is not entirely clear. Aim: To determine the association between quality of life, levels of physical activity and functional tests in actively working adults and older people. Material and Methods: Cross sectional assessment of 138 adults aged 40 to 50 years (53% women) and 119 older people aged 60 to 75 years (53% women) who were actively working in two public services. Quality of life was measured with the SF-36 questionnaire and usual physical activity was assessed with the International Physical Activity Questionnaire (IPAQ-short). Handgrip strength, the timed up and go (TUG) and chair stand test (CST) were used as functional tests. Results: Compared to older people, adults had better physical functional tests (P < 0.01). Older people had better scores in the mental health component (MHC) of quality of life (p < 0.05). In adults, the physical health component of quality of life (CSF) had a positive association with physical activity (Spearman Rho (rs)= 0.270; p = 0.01), grip strength (rs = 0.330; p < 0.01) and the TUG (rs = -0.229; p < 0.01). In older patients, CSM and CST were positively correlated (rs = 0.201; P = 0.029). In both groups, a correlation was observed between CSM, grip strength (adults rs = 0.283; p < 0.01; older people rs = 0.211; P = 0.02) and with TUG (adults rs = -0.197; P = 0.021; older people rs = - 0.212; p = 0.02). Conclusions: There is a positive correlation between quality of life and level of physical activity in working adults, which is not observed in older people. Adequate performance in physical functional tests is positively correlated with better quality of life (CSF and CSM) in adults and only with the mental health component in older people. (Rev Med Chile 2022; 150: 1625-1632) © 2022 Sociedad Medica de Santiago. All rights reserved.