BackgroundQuality of life of people with severe mental illness may be decrease by the high occurrence of metabolic and cardiovascular diseases. Physical fitness emerges as a modifying factor in this population through physical activity and this modification could influence in the quality of life of this population. The aim of the present study is to determine the contribution of physical fitness to the quality of life of people with severe mental illness.MethodsIn the current study, a physiotherapist and an occupational therapist assessed 62 people with severe mental illness. Physical fitness was measured with a range of 11 fitness tests that covered flexibility, strength, balance, and endurance. To assess quality of life the EQ-5D-3 L scale was used, which measures five dimensions (mobility, self-care, usual activities, pain-discomfort, and anxiety-depression).ResultsSignificant correlations are presented between the quality of life and primary variables of physical fitness (balance, endurance, and upper limb strength). Endurance explained 22.9% of the variance of the quality of life in people with severe mental illness. Functional reach added another 36.2% variance to the prediction of quality of life.ConclusionsThe results of the present study suggest that some variables of physical fitness are associated with quality of life in people with severe mental illness. The improvement in physical fitness of this population should be a primary objective.Trial registrationClinicalTrials.gov Identifier: NCT02413164 “retrospective registered” Registered Febr 2017.