Clinically amyopathic dermatomyositis (CADM) is a subgroup of dermatomyositis that manifests with characteristic cutaneous lesions and mild or no muscle involvement. It is known that rapidly progressive interstitial pneumonia with a poor prognosis can occur in patients with CADM. The anti-CADM-140 antibody is thought to be useful as a specific serological marker for CADM. We encountered 4 patients with the anti-CADM-140 antibody. All patients complained of cutaneous lesions and dyspnea. Chest X-ray films and CT scans showed ground-glass opacities (GGO) and consolidation in the lower lobes. All cases were treated with pulse methylprednisolone, cyclophosphamide therapy and cyclosporine. Three patients died of respiratory failure and 1 improved. Anti-CADM-140 antibody-positive cases are likely to have poor prognoses and should be treated by intensive therapy as soon as possible.