Objective To investigate the expression of Klotho in the myocardial tissue of the patients with chronic heart failure (CHF), and explore its relationship with myocardial fibrosis. Methods Myocardial tissue samples were collected from 60 CHF patients during cardiopulmonary bypass surgery in the Department of Cardiac Surgery, Kunming General Hospital of Chengdu Military Command from August 2013 to August 2014. According to the New York Heart Association (NYHA) Functional Classification, the patients were assigned into NYHA Ⅰ group, NYHA Ⅱ group and NYHA Ⅲ group (n=20 for each group). The mRNA level of Klotho in the obtained heart tissues was detected by real-time fluorescence quantitative reverse transcription PCR (RT-PCR). Enzyme linked immunosorbent assay (ELISA) was used to detect the serum level of carboxyterminal propeptide of typeⅠ procollagen (PⅠCP). The morphological differences were observed between the normal myocardium and heart failure myocardial tissue by HE staining. Results （1） HE staining showed hyperplasia of mayocardial collagen in CHF patients. （2）The mRNA level of Klotho was significantly decreased in both the NYHA Ⅱ group and NYHA Ⅲ group than in the NYHA Ⅰ group (both P<0.05), and was lower in the NYHA Ⅲ group than in the NYHA Ⅱ group (P<0.05). （3）The serum level of PⅠCP was highest in the NYHA Ⅲ group, followed by that in the NYHA Ⅱ group and then in the NYHA Ⅰgroup (all P<0.05). Conclusion Klotho expression is decreased in CHF patients, which may involved in its insufficient anti-aging effect and insufficient anti-myocardial fibrosis effect along with the deterioration of heart function.