Background and aims: The associations between physical fitness markers and liver volume in the general population are unclear. We investigated the associations of peak oxygen uptake (VO_2peak) and handgrip strength with liver volume in a general population sample. Methods and results: Data were taken from 1,531 German adults (51.3% women), aged 20 to 88 years, from two cohorts of the population-based Study of Health in Pomerania (SHIP-START-2 and SHIP-TREND-0). We analysed cross-sectional associations of VO_2peak and handgrip strength with liver volume derived from magnetic resonance imaging (MRI) by using multivariable linear regression models. These models were adjusted for age, sex, body fat mass, pre-existing type 2 diabetes, daily alcohol consumption, smoking status, and use of hypoglycaemic or antihypertensive medications. We observed significant associations of lower VO_2peak and handgrip strength with a smaller liver volume in the whole population, as well as in both men and women. In the whole population, a 1 L/min lower VO_2peak was associated with a 0.15 cm³ (95% confidence interval [CI]: 0.11 to 0.19; P < 0.0001) smaller liver volume for both sexes together. Similarly, a 1 kg lower handgrip strength was associated with a 7.05 cm³ (95% CI: 4.87 to 9.23; P < 0.001) smaller liver volume in the whole population. Conclusion: Our results derived from a large community-based sample showed that lower values of VO_2peak and handgrip strength were associated with a smaller liver volume. These results might explain the possible negative effects of sedentary lifestyle on liver volume – the sedentary liver.