Knowledge discovery is a wide ranged process including data mining, which is used to find out meaningful and useful patterns in large amounts of data. In order to explore the factors having impact on the success of university students, knowledge discovery software, called MUSKUP, has been developed and tested on student data. In this system a decision tree classification is employed as a data mining technique. With this software system all the tasks involved in the knowledge discovery process are kept together. The advantage of this approach is to have access to all the functionalities of SQL server and Analysis Services through single software. The study was carried out on the data from university students. According to results of the study, the types of registration to the university and the income levels of the students' family were found to be associated with student success. (Contains 3 tables and 6 figures.)