We provide a new classification for the neuronal ceroid lipofuscinoses (NCLs) that takes into account recent genetic and biochemical advances. This was originally developed by an international group with clinical, molecular genetic, biological, and morphologic interests, further revised by a panel of world experts in the NCLs, and is now updated in light of recent research findings. The aim is to provide young people, carers, and professionals with a diagnostic label that is informative, leads to effective clinical management of symptoms and in the future perhaps a cure, as well as aiding basic scientific and clinical research. We suggest that clinicians should aim to provide every child and family with detailed diagnostic information at clinical, biochemical, and genetic levels where possible, which the new classification allows in a gene-led hierarchical manner. The robustness and applicability of this updated new classification have been independently audited in the clinical setting using a series of patients previously diagnosed with NCL according to standard ultrastructural, biochemical, or genetic criteria.