Studies on peanuts from five deficient warehouses revealed that excess moisture, high temperature, and mechanical damage resulted in peanut quality deterioration as evidenced by low grade factors, increased free fatty acids, and increased carbonyl content. Levels of deterioration were related to kernel condition and length of storage. Loose shelled kernels were highly susceptible to deterioration. The research emphasizes the need for reduced mechanical damage, improved ventilation, elimination of moisture concentrations, and minimizing length of storage of peanuts of marginal initial quality.