Neuronal ceroid lipofuscinosis (NCL) is one of the most common progressive neurodegenerative diseases seen in childhood. NCL is inherited as autosomal recessive trait, and is characterized by the accumulation of 'ceroid lipofuscin' in neuronal and extraneuronal cells. Clinical features include seizures, ataxia, myoclonus, loss of vision, and mental and motor deterioration. Although the disease is widely seen across the world, there seems to be an information gap in Asian countries. To date, no comprehensive and detailed studies on NCL have been carried out in Turkey. However, one could predict that the disease is rather frequent in Turkey due to high rates of consanguineous marriages. Thirty-six Turkish patients were evaluated in this study. Sixteen (44.5%) patients were girls, and 20 (55.5%) were boys. Parents were consanguineous in 25 families (80%). In five families (14%), the disease was seen in two sibs. The diagnosis was based on clinical evaluation, and neurophysiological, neuroradiologic, enzymatic, and histopathological studies. Electron microscopic study was the main diagnostic laboratory test. Three patients were classified as infantile NCL, 11 were late infantile NCL, 5 were juvenile type NCL and 17 patients were Turkish variant NCL. In juvenile type, major initial symptom was visual impairment, whereas in all other types seizures were predominantly the first symptom at the onset of the disease. The initial symptoms of Turkish variant NCL were similar to those of late infantile type. Similar age at clinical symptoms and the presence of visual symptoms were common features of Turkish variant and juvenile NCL. Compared to late infantile NCL, Turkish variant, showed a more severe course regarding seizures. Electroencephalogram (EEG) showed abnormal features predominantly in Turkish variant, and were remarkable for occipital spikes. In patients with Turkish variant magnetic resonance imaging of the brain showed brainstem involvement, especially pons, in all patients except one; cerebral and cerebellar atrophy were seen with a slower course compared to late infantile NCL. Clinical picture of NCL in advanced stages of the disease was similar regardless of the subtype.