Cardiotrophin-1 is known to be a key regulator of energy homeostasis, as well as glucose and lipid metabolism in vivo. However, there are inconsistent results of the association between cardiotrophin-1 and obesity in humans, possibly confounded by hyperglycemia. Therefore, the aim of this study was to investigate the relationships among cardiotrophin-1 levels, overweight and obese individuals without diabetes in a Chinese population. The median (inter-quarter range) serum cardiotrophin-1 levels were 447.9 (230.9, 913.9), 350.6 (201.1, 666.5), and 288.1 (162.3, 572.4) pg/ml in non-diabetic subjects who were of normal weight (n = 522), overweight (n = 203), and obese (n = 93), respectively (trend test p < 0.001). Subjects who were overweight and obese had significantly lower cardiotrophin-1 levels than those with normal weight. The multivariate linear regression analyses showed that overweight (beta = -338.718, 95% CI = -552.786 ~ -124.651, p < 0.01), obese (beta = -530.275, 95% CI = -832.967 ~ -227.583, p < 0.01), and smoking (beta = -377.375, 95% CI = -654.353 ~ -100.397, p < 0.01) were negatively related to cardiotrophin-1 after adjusting for age, gender, HOMA-IR, hypertension, total cholesterol, HDL, triglyceride, eGFR, ALT, and alcohol drinking. The results of this study provided epidemiological evidence that non-diabetic subjects who were overweight or obesity had significantly lower cardiotrophin-1 concentrations than those with normal weight, and both obesity and being overweight were inversely associated with cardiotrophin-1 levels.