In modern business philosophy, business should be customer oriented and the implementation of the main principles of continuous improvement, justifies the importance of evaluating and analyzing customer satisfaction. In short, customer satisfaction is considered as baseline of standard and the excellence of performance for many business. It also helps to identify the potential market opportunities. The methods used by the writer in this research is quantitative method. Data used in this research are primary data and secondary data. Data analysis methods used in this research are descriptive statistic, validity test, reliability test, normality test, correlation test, coefficient of determination test, simple linear regression analysis, and Z test. Based on the data analysis, the coefficient of linear regression = 0.442 (positive). This means that service quality (X) has positive influence towards customer satisfaction (Y). The result of hypothesis test by using Z-Test, the value of Zcount = 4.43. It means that hypothesis alternative is accepted because Zcount (4.43) > Ztable (1.96). Therefore,service quality has significant impact on customersatisfaction at Gober Petshop Medan.