A case of a patient with epithelioid sarcoma, an entity only recently recognized, is reported. It illustrates the problems which the lesion presents in diagnosis and, since it is likely to be seen first by the orthopaedic surgeon because it usually affects an extremity, he should be aware of its character. It is typically slow-growing and is often misdiagnosed initially as a benign process. It often recurs and, in 30 per cent of cases, will metastasize.