As the natural history of frozen shoulder is poorly documented, a prospective study of 40 patients followed up for 40-48 months (mean 44 months) is described. The range of movement was significantly less than age- and sex-matched controls. Objective restriction was severe in five patients and mild in a further 11. Patients were often unaware that shoulder range was impaired. Dominant arm involvement, manual labour, and mobilisation physiotherapy were associated with a less satisfactory outcome. We conclude that, while objective restriction persists, there is little functional impairment in the late stage of frozen shoulder.