Biological membranes are interesting interfaces, at which important biological processes occur. In addition to integral membrane proteins, a number of proteins bind to the membrane surface and associate with it. Posttranslational lipid modification is one important mechanism, by which soluble molecules develop a propensity towards the membrane and reversibly bind to it. Membrane binding by insertion of hydrophobic lipid moieties is relevant for up to 10% of all cellular proteins. A particular interesting lipid-modified protein is the small GTPase Ras, which plays a key role in cellular signal transduction. Until recently, the structural basis for membrane binding of Ras was not well-defined. However, with the advent of new synthesis techniques and the advancement of several biophysical methods, a number of structural and dynamical features about membrane binding of Ras proteins have been revealed. This review will summarize the chemical biology of Ras and discuss in more detail the biophysical and structural features of the membrane bound C-terminus of the protein.