The number of sales transactions that occur every day makes the sales transaction data increase. Sales transaction data is only used as an archive for a store. Due to the large number of customer requests for goods, there is a shortage of goods. Shortage or stock of goods in a store/company will have a very bad impact on the success and sales of buying and selling transactions. To prevent this, a system is needed that can help to find out early about the availability of goods in the store. The method used in this research is the association rule method using a priori algorithm. The a priori algorithm is a data mining technique to find combinations of items in the database, the results of the research conducted, the a priori algorithm can make it easier to find patterns of combinations of items in the dataset. The information obtained can help decision makers to determine the priority of stock inventory.