Objectives To analyse the clinical characteristics and prognosis of acute exacerbation (AE) in patients with idiopathic pulmonary fibrosis (IPF) and pulmonary emphysema.Design A multicentre retrospective cohort studySetting Two university hospitals in JapanParticipants Patients admitted to hospitals due to AE of IPF diagnosed based on a multidisciplinary discussion.Interventions NonePrimary and secondary outcome measures 90-day mortality rateMethods We retrospectively analysed consecutive patients with AE of IPF, with or without pulmonary emphysema, admitted to two university hospitals between 2007 and 2018.Results Among 62 patients (median age, 75 years; 48 men) admitted for AE of IPF, 29 patients (46%) presented with concomitant pulmonary emphysema. There was no significant difference in the arterial partial oxygen pressure/fraction of inhaled oxygen (P/F) ratio or other laboratory and radiographic data between patients with and without emphysema. The 90-day mortality rate was significantly lower in patients with emphysema than in those with IPF alone (23% vs 52%, p=0.03). The median survival time was significantly longer in patients with emphysema than in those with IPF alone (405 vs 242 days, p=0.02).Conclusion Patients with IPF and emphysema had better short-term survival after AE than those with non-emphysematous IPF.