The serum levels of muscle enzymes have been considered normal in patients with eosinophilic fasciitis (EF). We observed elevated serum aldolase levels in 3 patients with EF. Serum creatinine kinase levels were within the normal range. We measured the aldolase levels longitudinally. In all patients, the levels decreased to the normal range after oral corticosteroid treatment, and skin sclerosis improved. Afterwards, serum aldolase levels increased again, with the recurrence of skin sclerosis. These observations suggest that serum aldolase level may be a useful indicator of disease activity.