iMol is a free molecular visualization application for Mac OS X operating system. The program is an indispensable tool for chemists and molecular biologists. iMol allows loading molecules using several file formats: PDB, XYZ, MOL2, HIN, CAR, ALC, BIO. The molecules can be saved as PDB, XYZ or BIO files. The BIO file stores all view and rendering settings (e.g. colors, lighting, orientation of molecules). iMol can easily handle both small and large molecules, it can load multiple molecules, move and rotate them independently.