GM1 gangliosidosis is an autosomal recessive lysosomal storage diseasewhich is characterized by the accumulation of GM1 ganglioside, sphingolipids,glycoprotein bound oligosaccharides and keratan sulphate. Three majorclinical forms have been identified depending on the enzyme levels, thetiming of onset and severity of the manifestations; infantile form being themost severe. We herein present the clinical features and the histopathologicalfindings of the central nervous system of two cases with type I infantilegangliosidosis; the first one had been diagnosed when she was 8 months oldand died at the age of 3; the second one had been diagnosed when he was 10months old and died at the age of 2. Correlations between clinical featuresand histopathological findings have been discussed. Postmortem examinationof both cases revealed a severe cortical thinning of cerebrum and cerebellum,accompanied by ventricular dilatation. Light microscopic evaluation ofcerebral, cerebellar and brainstem sections demonstrated a distortion ofnormal parenchymal structures and presence of cellular aggregates bearinglarge, foamy and eosinophilic cytoplasm. Clinical records of the cases revealeda history of delayed mental and motor development, and frequently recurringinfection episodes for both cases. Postmortem histopathological examinationof such cases enables us to thoroughly identify and describe the multisystemic organ pathologies stemming from gangliosidosis. In this report,we aim to put an emphasis on the specific postmortem neuropathologicalfindings in GM1 gangliosidosis. For a definitive diagnosis, documentation oflow ß-galactosidase enzyme levels in leucocytes is a must.