In the information and communication era, management information systems play an undeniable role in organizations.  Bank Parsian is a Iranian banking and financial services company, which has a network of 273 banking branch, known as the largest Iranian private bank. This research examines the gaps in customer relationships systems in Bank Parsian based on characteristics of management information system and in this study tries to answer this question “is there a significant relationship between customer relationship management (CRM) information systems and performance of Bank Parsian? The study place is the territory between the employees of Parsian Bank in Tehran. The study was conducted for 6 months in 2015 and the population is consisted of all managers and experts.  This study conducts in Parsian Bank, which the number of employed managers and experts about 168 people estimated. In this study, simple random sampling was used and sample size was determined using Cochran formula. The sample was calculated according to confidence level 95% and probability of error 5% and the population size was 168, the sample size is 117 people. The results showed there is a significant relationship between customer relationship management (CRM) information systems and internal performance and process performance and financial performance in Parsian Bank. As well as there is a significant relationship between customer relationship management (CRM) information systems and performance in Parsian Bank.