The authors present a study of 50 patients with late onset Krabbe''s leukodystrophy (LOKL), including 27 from a pooled European Series collected in 1987, and 23 published between 1906 and 1987. In Europe, the disease appears to be relatively frequent in Sicily and exceedingly rare in Sweden. Most cases started before the age of 5 years. The initial signs consisted mainly of progressive motor impairment, although, characteristically, visual failure was the initial manifestation in 25% of patients. Low nerve conduction velocities and a high protein content in the CSF were only present in 50%. There was no age-linked symptomatic predominance. The pace and length of the disease was very variable, but in one-third of the children before the age of 3 the course was remarkably rapid. There was no difference in the residual activity of galactosylceramide galactosidase in LOKL compared to the early infantile form.