For decades the way of viewing of the cell membrane has changed considerably. At the beginning of the twentieth century the cell membrane was visualized as a lipid bilayer. Following researches have discovered that the cell membrane contains also proteins. In 1972 Singer and Nicolson introduced the division of membrane proteins into peripheral and integral proteins. Singer and Nicolson had also conduc-ted research on cells fusion, which have laid the foundation of the membrane model as a fluid mosaic of lipids and proteins. The Singer and Nicolson model in many aspects is still valid. Nowadays it is well known that membranes contain differently arranged regions which are called membrane domains. The study of the membrane domains is extremely fascinating but also a difficult challenge, because the results depend on methods used in the research. Based on numerous studies it can be concluded that the membrane domains are involved in the regulation of several biological processes such as cell adhesion, sorting and transport of lipids and proteins, and also signal transduction. The latter process is controlled by lipid rafts in which facilitated interaction between proteins and lipids have been observed. It should be remembered that ceramide- enriched microdomains and glycosynapses are included among membrane domains. The variety and diversity of membranes domains make membrane biology very complex but also very interesting an object of research.