Acute admission to hospital for an exacerbation of chronic respiratory disease (CRD) may impair skeletal muscle mass and function. We measured quadriceps thickness (Qthick), as a surrogate marker of muscle mass, at hospital admission, discharge, 6 weeks and 3 months in 55 patients with CRD. Qthick fell by 8.3% during the period of hospitalisation, which was sustained at 6 weeks, and only partially recovered at 3 months. Sustained loss was most marked in patients readmitted during the follow-up period. Acute reduction in quadriceps muscle mass occurs during hospitalisation, with prolonged and variable recovery, which is prevented with subsequent hospital readmission.