The quantitative and descriptive study involved an examination into the relationship between two factors, seasonality and promotion, and the accuracy of the demand forecast for forecast leaders of U.S. processed meat manufacturers. The purpose of the study was to assess whether promotion and seasonality affect the accuracy of demand forecasts for Company ABC, a large U.S.-based manufacturer and distributor of processed meat. A single case study design and a custom survey were used to collect the data used to test the hypothesis and answer the following research question: Do seasonality and promotion affect the accuracy of demand forecasts for the forecasting leaders of Company ABC. A pilot study was conducted to validate the custom survey before it was used to collect data from the sales personnel who participated in the study. The key findings of the study indicated that seasonality and promotion do affect the accuracy of demand forecasts for Company ABC. The findings also indicated that seasonality and promotion are equally significant in terms of their effect on the accuracy of a demand forecast for processed meat.