Due to the increasing importance of Internet Banking and the critical actions taken by banks in order to offer Internet banking services in Iran and also according to the increasing number of people using Internet Banking services, it is essential for bank marketers to understand Internet banking customers better. Only through this comprehension the marketers are able to develop strategies and tactics to attract and sustain their customers. In this study we have investigated the influential factors in Internet banking systems quality. Electronic questionnaires were applied for data gathering through a case study of Mellat Bank Internet banking customers. According to research findings and conclusions, it is suggested to apply internet banking customer’s viewpoint in designing internet banking systems to provide customers with the opportunity of using Internet banking services and achieving good experiences. In this way, Iranian banks can differentiate their net-based services from their competitors.