The aim of this study was to determine whether skin ulcer can be used as a predictive and prognostic factor of acute/subacute interstitial lung disease (ILD) in Japanese patients with dermatomyositis (DM). We reviewed the medical records of 39 consecutive DM patients who were admitted to Tokyo Metropolitan Komagome Hospital from January 2000 to December 2009. The mean follow-up period was 63.9 ± 51.6 months. Fifteen patients had acute/subacute ILD and 11 patients had chronic ILD. Seven out of 15 acute/subacute ILD led to respiratory failure and 3 of them died due to ILD. Skin ulcers were observed in 5 out of 15 patients with acute/subacute ILD (33.3 %) and in 2 out of 24 patients without acute/subacute ILD (8.3 %). The presence of skin ulcers was revealed to be a significant predictive factor for acute/subacute ILD among various parameters by multivariate analysis. In the 15 patients with acute/subacute ILD, the presence of skin ulcers was a significant poor prognostic factor (p = 0.0231) and the cumulative survival rate of patients with skin ulcers was 53.3 % for 12 months. Skin ulcer is a significant predictive and prognostic factor of acute/subacute ILD in patients with DM.