PT X Indonesia is one of the foreign companies from South Korea that engaged in producing additional ingredients for animal feed. Located in Pasuruan-East Java, PT X is one of the industries producing L-Lysine and L-Tryptophan essential amino acids. L-Lysine and L-Tryptophan products are stimulants for animal feed which are exported to several countries. The planning of the production process is based on requests from the headquarters of PT X Indonesia in South Jakarta, Indonesia. To meet the needs of export products to several countries, PT X requires careful planning in providing the products. One of the determining factors in planning and providing products accurately, effectively, and efficiently is demand forecasting. This study aimed to forecast the export demand of L-Lysine. Historical data used for forecasting was time-series data from September 2019 to January 2020. The best ARIMA model combination chosen for forecasting was (1,0,1) because both the p-values for the AR and MA models are significant and it has the smallest Mean Square Error (MSE). Forecasting results use the ARIMA model showed that L-Lysine export for four weeks was in a range of 2,596.47 tons to 2,597.5 tons with a total of 10,387.9 tons and an average of 2,596.975 tons per week.