Juvenile neuronal ceroid lipofuscinoses (JNCL) is the most common type of the neuronal ceroid lipofuscinoses (NCLs), a group of pediatric neurodegenerative diseases. In this chapter the genetic and biochemical basis, pathogenesis, clinical features, histopathological features, diagnosis and therapeutic strategies of the JNCL are reviewed. The premature death of the patients and subnormal life quality are inevitable due to the lack of understanding of pathogenesis and limitation in treatment. Hence we are still a long way to conquer the disease.