Objective: The aging-associated changes in body composition result in an increased cardiometabolic risk. A tremendous reduction of cardiovascular morbidity and mortality can be obtained by statin therapy. Statins are well tolerated, with myopathy as the most serious negative side effect. Some recently published studies indicate that the incidence of type 2 Diabetes might be increased during intensified statin therapy. The aim of our study was to investigate whether statin therapy has an influence on the aging-associated changes in fat-free mass(FFM). Methods: A total of 3,280 persons attending a medical outdoor center between January 2005 and July 2011 were assigned to 3 age groups from <60 to >75 years. Clinical data, body mass index (BMI), and body composition were evaluated in the different age groups in patients with and without statin therapy. To analyze the impact of statin use on FFM, we regressed a patients FFM on an interaction term between statin use and age and other control variables. Results: Aging was associated with a decrease in BMI and FFM, while fat mass continuously increased up to the age of >75 years. This was paralleled by a continuous increase in fasting glucose levels in patients with and without statin therapy. The loss of FFM between the age group <60 years and >75 years was more pronounced in statin-treated patients(10.88%) than in non-statin users (8.47%). Creatine phosphokinase values revealed a decrease of 7.77 U/l between the age groups <60 and >75 years in non-statin users and of 14.75 U/l in statin users. Statistical analysis indicated that the effect of statin therapy on FFM is more pronounced in younger than in older patients. Conclusions: Patients under statin therapy seem to be more vulnerable to the aging-associated lowering of FFM. Diagnostic procedures and interventions to prevent a loss of muscle mass might be of particular advantage in elderly patients under statin therapy.