A 49-year-old female was referred to our hospital due to high serum creatine kinase (CK) (2,605 IU/L) and serum cardiac troponin T (cTnT) (0.342 ng/mL) levels. She had no other complaints and further examinations suggested no signs of cardiac disease. Additionally, the serum cardiac troponin I (cTnI) levels were normal. She reported having gradually felt difficulty in walking upstairs. A biopsy indicated skeletal muscle sarcoidosis with positive staining for cTnT. Steroid therapy immediately resolved her muscular symptoms with a normalization of the serum CK levels. Since the serum levels of cTnI were normal, the concomitant measurement of cTnT/cTnI might be useful to diagnose skeletal muscular disease biochemically in such cases.