Three patients with adult-onset neuronal-ceroid lipofuscinosis (Kufs' disease) are presented. Two cases were familial (autosomal recessive inheritance) and 1 case was possibly sporadic. The main clinical feature was progressive deterioration of cognitive functions. In 2 siblings, aged 37 and 41, dementia was associated with personality and behaviour changes, suggesting a psychotic disorder and with dysarthria and tic-like dyskinetic movements. In a third patient, dementia was only associated with an asymptomatic pigmentary retinal degeneration. CT scan revealed diffuse cerebral atrophy in all cases. Diagnosis was established by brain biopsy in 2 cases. Autofluorescence emission and absorption spectra from the abnormal pigment was studied and was not found contributive.