Early diagnosis is mandatory for avoiding further cases in families with hereditary metabolic brain disorders. This review lists the most important clinical symptoms and neuroradiological findings at the early stage of the seven most common childhood neuronal ceroid lipofuscinoses (NCL) types. In the infantile type the typical magnetic resonance imaging (MRI) findings can be seen even before the clinical signs. In the classic late infantile type (CLN2), MRI is less informative but in this and in the variant late infantile type CLN6 the characteristic neurophysiological findings are present at an early stage, although not in the Finnish variant CLN5. In the latter, the clinical diagnosis depends on ophthalmological and MRI findings. The combination of ophthalmological deficits and vacuolated lymphocytes is highly characteristic of the juvenile type (CLN3). A new NCL type, Northern epilepsy (CLN8), is also briefly reviewed.