This study aims to discover association patterns from customers' purchase, these patterns later on known as reference for the store to supply goods. Mapongs store is one of the online shops that is developing quite rapidly, however, Mapongs Store is still difficult to determine the supply of stock of goods to be sold, so this has an impact on decreasing sales figures. To solve this problem, the method used in this study is the Association rule using the FP Growth algorithm. Analysis of sales data obtained with the Association rules Method using the FP Growth algorithm, namely the greater the minimum support and minimum confidence used, the fewer itemset and rules will be formed. In this study, if the minimum support is 50% and the minimum confidence is 80%, it will produce 211 rules. So, the rules in this study can be used as information for sellers to find out what products buyers often buy at this Mapongs Store. All Rules produced in this study have a Lift ratio value of more than 1.00 so they can be used as a reference in determining the relationship between product sales to optimize the results of sales analysis for sellers