This study investigated the key factors contributing to aflatoxin contamination in peanuts from farm to processing factory using questionnaires. It involved 90 stakeholders, including 30 farms, 30 shelling stations, and 30 processing factories. Statistical analysis was conducted to identify differences in adherence to good hygiene practices among stakeholders. The study selected eight peanuts supply chains based on their compliance with good hygiene practices and measured their level of contamination with aflatoxin B1. Regression analysis was performed to determine the impact of each stage on aflatoxin contamination levels. The findings highlighted poor hygiene practices, especially at upstream stages, contributing to aflatoxin contamination. The study recommended practical measures to minimize contamination, emphasizing the need to enforce recommended hygiene practices, particularly at upstream stages, to control aflatoxin contamination throughout the manufacturing chain.