In present project, the purpose is the parallelization of the main parts of ab initio molecular orbital codes, and gathering these codes into a parallel ab initio molecular orbital program package. Basically, the program has been coded taking into account the possibility of vectorization of the codes. Several new techniques in computations have been implemented into the program, and in addition, developments of new methods and algorithms have been carried out, as well as the aplication of those methods to chamical problems in initerest. For exapmle, Hirao and Nakano have developed multireference Mphiller-Plesset (MRMP) method which can calculate energy levels of the ground and excited states and potential energy surfaces for chemical reactions quantatively. We have implemented this method into the famous program packages, HONDO and GAMESS,and parallelized the integral trasfomation code in an MRMP routine. We also developed a new type of spin-polarized correlation functional in a formalism of density functional theory, and implemented the program package. The parallelization of this code is now in progress. The Obara's code of molecular integral has also been implemented into GAMESS.