Proteins are macromolecules consisting of 20 different amino acids and have many biological functions. Native state represents a unique, stable and kinetically available state of minimal free energy in which protein should be folded so that it can perform its biological function. The process in which polypeptide chain is taken into its native state is called the mechanism of protein folding. Understanding the mechanism of protein folding helps us to predict the three-dimensional protein structure on the basis of its primary structure and also have a significant role in medicine because misfolded proteins cause incurable neurodegenerative diseases. Advances in understanding the mechanism of protein folding open up many opportunities to analyse the cause of neurodegenerative diseases and represent the first step towards finding drugs. Because of its biological importance there are a lot of books and scientific papers on proteins and their folding. For now, there are several models of protein folding, but general model that would be applicable to wide range of proteins still does not exist.