Gangliosides are a large group of sialylated glycosphingolipids that are widely expressed in mammalian tissues. Gangliosides are found in most tissues of the body, but they are particularly abundant in brain and nervous tissues. The differential distribution of gangliosides in various tissues is a strong indication that they play impor tant roles in specific functions in different tissues. Glycosphingolipids (neutral glycosphingolipids and gangliosides) are formed biosynthetically within the Golgi apparatus. Gangliosides are involved in a number of interaction processes with cell external ligands and cell membrane components. Gangliosides seem to be involved in cell-to-cell interaction and regulation of cell signaling. They can be receptors of proteins, viruses and bacteria (GM1 is a receptor of Cholera Toxin). Gangliosides are also playing a role in the cell proliferation. The differentiated cells in human melanoma are expressing GD3 and other b series gangliosides such as GQ1b, whereas GM3 can be involved in the differentiation of some lymphocytic cells.