Current research is designed to consider the relationship between decision making style and quality of services in Melli bank of Sanandaj. We have considered all staffs of Melli bank of Sanandaj as population (statistical society). This study is descriptive – correlation and purposely is practical and collecting information is based on survey information and in terms of time is sectional-lateral and based on equations content model. To measure basic concepts, we have used decision making style questionnaire of Hadi Zadeh and Tehrani's model which has 5 dimensions: rational, intuitive, dependency, momentary and avoidance and also includes 25 questions. The quality of services questionnaire of Ibrahimi's model includes 25 questions. The social sample involves 170 staffs of Melli bank which have been selected by accidental sampling. We have used Chronbach's Alpha to calculate reliability which is 0.917 and 0.915, respectively. To observe the relationship between two variables, we have used Pearson correlation testing and multiple regression testing. The final findings show that there is significant relationship between decision making style and it's dimensions and the quality of services among staffs of Melli bank. The most effective dimension is relational.