The purpose of this research is to test and analyze the influence of Product Quality (KPro), Price (H), Promotion (P) and Place (T) to the purchasing decision (KP) of customers who have ever purchased and serviced their Kawasaki motorcycle at PT. SURAPITA UNITRANS Dealer Surabaya. Meanwhile, the linear regression is carried out in order to show the influence magnitude of Product Quality (KPro), Price (H), Promotion (P) and Place (T) partially to the customersâ purchase decision (KP) is used as the analysis technique. The population is 100 respondents. The result of determination coefficient (R2) is 0.706 atau 70.6%, which means that the contribution among independent variables that has been selected as research model to the purchasing decision (KP) of customer is big, while the remaining is contributed by other variables. The result of model feasibility test shows that regressions model can be used to predict the influence of marketing mix which consists of Product Quality (KPro), Price (H), Promotion (P) and Place (T) to the purchasing decision (KP). The result of partial test shows that from four variables which have been used as research model i.e.: Product Quality (KPro), Price (H), Promotion (P) and Place (T) have a significant and positive influence to the purchasing decision (KP). It indicates that from the acquisition of significance level of each variable is less than α = 5%. It indicates that this variable have dominant influence to the purchasing decision (KP)of customers who have ever purchased and serviced the Kawasaki motorcycle at PT. SURAPITA UNITRANS Dealer Surabaya.Keywords: Product Quality (KPro), Price (H), Promotion (P), Place (T) And Purchasing Decision (KP)