The adsorption of large molecules, such as proteins and colloids, from solution to solid surfaces is often dominated by steric exclusion of molecules already present on the surface. This talk will review some theoretical approaches to the quantitative description of the adsorption kinetics. In particular, I will describe the Random Sequential Adsorption (RSA) theory for irreversible adsorption and experimental studies that demonstrate its accuracy. I will also present recent work on the reversible binding of macromolecules on heterogeneous surfaces.