The course provides knowledge to deal with calculations of biological interest. Principles of biology and chemistry are delivered together with a deep understanding of the methods used to compute chemico/physical properties of molecules such as organic and peptidic ligands, proteins and nucleic acids. Standard and advanced computational techniques are described in details and many applications are illustrated. Ligand/protein docking, virtual screening, homology modelling, molecular dynamics, free-energy calculations are some examples. Great attention is dedicated to the application of these methods in drug design through rational approaches and more automated protocols.