Luscus is the program for graphical display and editing of molecular systems. The program allows fast and easy building and/or editing different molecular structures, up to several thousands of atoms large. Luscus can also visualize dipole moments, normal modes, molecular orbitals, electron densities and electrostatic potentials. In addition, simple geometrical objects can be rendered in order to point out a geometrical feature or a physical quantity. The program is developed as a graphical interface for MOLCAS program package, however it's adaptive nature makes possible using luscus with other computational program packages and chemical formats.