Natural and artificial contaminants in poultry feed may result in deteriorated feed quality, reduced performance, and increased incidence of disease in poultry, ultimately leading to a significant economic loss for producers. Moreover, since poultry are raised to produce meat and eggs for human consumption, contaminants in poultry feed may also pose risks to human health. This chapter focuses on those contaminants considered to pose the most significant risks to poultry and human health: mycotoxins, dioxins, and bacterial pathogens. Each section will discuss the negative effects of these factors as well as possible control measures that may be implemented to reduce feed contamination and secure feed and food safety.