1. A case is described of three giant-cell tumours, the first in 1966 in the lower left femur, the second in 1968 in the upper right femur, the third later in 1968 in the upper left femur. 2. None of the tumours could be described as frankly malignant. 3. Despite a lapse of four years it is still not possible to decide whether the first tumour had metastasised or whether all three arose independently by multifocal origin.