We describe a patient who, three years after the onset of an olivopontocerebellar atrophy, developed a right cerebral tumour. The cerebellar symptomatology also included, as in other cerebellar patients previously described, a peripheral dysgraphia. Because this deficit of writing is generally reported in patients with right cerebral lesion, the authors hypothesized that functional alterations of supratentorial structures preceding the tumour by years may be able to damage the neural substrates connecting cerebral and cerebellar structures and to produce cerebellar atrophy.