This study was conducted to determine the margins of safety between no-observed-effect levels (NOELs) and estimates of daily intake for 809 flavouring substances evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) between 2000 and 2004. Estimates of daily intake were calculated using two methods, the maximized survey-derived daily intake (MSDI) and the possible average daily intake (PADI). The MSDI estimates were based on the production volume of flavouring agents as reported by industry, whereas the higher more conservative PADI estimates were derived by multiplying the anticipated average use level of a flavouring substance in each of 33 food categories by the average amount of food consumed daily from that food category and summing the intake over all 33 food categories. These intake estimates were used to calculate the margins of safety for the flavouring agents to determine whether adequate margins of safety would still exist in the event that the MSDIs used by JECFA to evaluate the safety of flavouring substances underestimated daily intakes. Based on the calculation of the margins of safety using the MSDI values, 99.9% of the 809 flavouring substances evaluated by JECFA have margins of safety of greater than 100. In comparison, 98% of flavouring substances have margins of safety of greater than 100 when the margins of safety were calculated from PADI values. The results indicate that if the MSDI estimates used by JECFA for the evaluation of the safety of flavouring substances were underestimated, a wide margin of safety exists for all but a few of the flavouring substances even when intakes were estimated from PADI values.