The purpose of this Final Project is to find out the marketing relationship influence to customer retention in Alfamart Kauman Semarang. The population and samples from this research were people who live in the coverage area of Alfamart Kauman Semarang, with a population of 569 people taken as sample of 100 people. The methods of data collection used in this research were interview, literature study and questionnaires. The questionnaires use a semantic differensial with 10 point scale and the methods of collecting the sample used were incidental sampling and purposive sampling. The data analysis technique used was Simple linear regression. Based on the calculations using IBM SPSS 22.0, the t test result (8,206) was bigger than t table (1,984) and had a significance (0,000) less than level significance of 0,05. So, the result of the research explained that the relationship marketing had a positive and significant effect on customer retention. The result of R square is 40,7% had a meaning that 40.7% of the Customer Retention variance (Y1) could be explained by changes in the Relationship Marketing (X1) variable, while the remaining of 59.3 was explained by other factors outside the model, such as: rewarding, differentiation, and belonging. To the future research can observe other factors such as rewarding, differentiation, and belonging.