Change in the banking business model from product orientation to client orientation is the main cause for the appearance of the need for modernisation and transformation of the banking IS in order to offer the customer a comprehensive range of personalised banking products and services. From a technological point of view, the solution lies in the introduction of service-oriented architecture and business process management systems. The first part of the master's thesis presents the reasons and the need for the modernisation of the bank and transformation of the banking IS. Based on a business case in which an existing deposit IS was upgraded and modernised, the second part provides technical, organisational and socio-psychological aspects of its redesign and the introduction of new technologies. The progressive transformation of the existing IS has been shown to be the only possible and correct choice in the given organisational structure of the bimodal IT. Furthermore, the hybrid model of software development as a combination of the waterfall model and the agile Scrum methodology has been proven to be very effective in software development aimed at bringing greater agility. In the end suggestions and guidelines are given to streamline further transformation of the existing system, a comprehensive approach to transformation is explained, as well as the need for a new integrated information architecture and technology, and the possibilities of a comprehensive agile software development.