Baby diapers are complex products consisting of multiple layers of materials, most of which are not in direct contact with the skin. The safety profile of a diaper is determined by the biological properties of individual components and the extent to which the baby is exposed to each component during use. Rigorous evaluation of the toxicological profile and realistic exposure conditions of each material is important to ensure the overall safety of the diaper under normal and foreseeable use conditions. Quantitative risk assessment (QRA) principles may be applied to the safety assessment of diapers and similar products. Exposure to component materials is determined by (1) considering the conditions of product use, (2) the degree to which individual layers of the product are in contact with the skin during use, and (3) the extent to which some components may be extracted by urine and delivered to skin. This assessment of potential exposure is then combined with data from standard safety assessments of components to determine the margin of safety (MOS). This study examined the application of QRA to the safety evaluation of baby diapers, including risk assessments for some diaper ingredient chemicals for which establishment of acceptable and safe exposure levels were demonstrated.