Stocks are securities issued by a company. In buying and selling stocks, proper analysis is needed to make a profit. One of the ways to make a profit when selling and buying stocks is to have a recommendation system for making stock buying and selling decisions. In this research, a stock trading recommendation system was carried out using Fuzzy Logic using PT Bank Central Asia Tbk (BBCA.JK) and Bitcoin (BTC) stock data obtained from Yahoo.Finance website in one day from October 2022 to October 2023. Based on research that has been carried out using Mamdani Fuzzy Logic. Based on the evaluation results, the constructed inference engine will provide an insight into the effectiveness of buying or selling decisions based on input values of opening and closing prices. This engine can be employed to assist in making buy or sell decisions based on the opening price and predicted closing price whereas the decision were evaluated based on the stock history prices.