Background: Cardiorespiratory fitness (CRF) is inversely associated with metabolic diseases and adiposity markers. Aim: To assess the association of CRF with body mass index (BMI), waist circumference (WC) and obesity in a representative sample of the Chilean population. Material and Methods: Data from 5,958 participants in the Chilean National Health Survey 2016-1027 aged 15 years or above were analyzed. CRF was estimated by an equation that included sociodemographic, anthropometric and health-related data and expressed in metabolic equivalent units (METs). The association between CRF and adiposity was assessed using linear and Poisson regression models and the results were presented as Prevalence Ratio (PR). Results: One MET increment in CRF was associated with a 3.27 kg/m2 (95% confidence intervals (CI): -3.35; -3.2) and 4.56 kg/m2 (95% CI: -4.67; -4.46) lower BMI in men and women, respectively. Waist circumference was 6.7 cm [95% CI: -6.98; -6.42] and 9 cm [95% CI: -9.33; -8.67] lower per 1-MET increment in CRF. With one MET increment, the probability of being obese was 34% (PR = 0.66 [95%CI: 0.63; 0.69]) and 36% (PR = 0.64 [95%CI: 0.61; 0.67]) lower in men and women, respectively. The probability of having a central obesity was 26% (PR = 0.74 [95%CI: 0.71; 0.77]) and 30% (PR = 0.70 [95%CI: 0.68; 0.73]) lower in men and women, respectively. Conclusions: A higher estimated CRF was associated with lower adiposity levels and a lower risk of being obese in both men and women. Public health policies aiming to increase physical activity are needed to increase the CRF of the Chilean population.