A system and method are provided for integrating core banking business processes which includes a business platform in which two or more selected banking processes common to the core banking business are integrated. The business platform includes at least one database for sharing data between the core banking business processes and to provide the system with customer and business information. The business platform invokes a basic business rule library formed of two or more basic business operations to be implemented and a common function library which includes at least one common function program which is called by the basic business operations. One or more application business subsystems each formed of a combination of the basic business operations are called by the business platform to perform selected operations as required by a particular banking transaction.