This study aims to propose a new approach for service quality improvement through simultaneous measurement of all data and indicators affecting service quality and related to each service along with each other, and to find the importance and relationship between these indicators and suggesting service quality improvement solutions. The proposed model named quality mining is based on data mining in service quality. As a case study, all the one-year services registered by the information technology service management (ITSM) system of a manufacturing company have been analysed. Clustering, correlation, and rule learner data mining methods have been used in the studied organisation. Findings indicated a direct relationship between the performance of the organisation and satisfaction regarding the services provided. The improvement suggestions presented for the studied organisation were related to the performance improvement of employees/functions. The factors affecting service quality were also determined.