ABSTRACTBinding of three mutagens, known to occur in fried or broiled foods, by thirteen different types of dietary fiber was investigated in vitro. Nonspecific binding by other food polymers was minimized by using protease and amylase treatment. Water‐insoluble fiber components were responsible for most of the binding capacity. Generally, a slightly larger proportion of 2‐amino‐3,4‐dimethylimidazo [4,5‐f]quinoline (MeIQ) than of 2‐amino‐3‐methylimidazo [4,5‐f]quinoline (IQ) and 2‐amino‐3,8‐dimethylimidazo] ‐4,5‐f]quinoxaline (MeIQx) was bound. There was a significant correlation between Klason lignin content and binding of mutagens. Optimum pH for binding was between 4 and 6. Dietary fiber from sorghum had the highest binding capacity, which could be due to the presence of a large Klason lignin fraction.