Abstract: In a H2SO4 medium and in the presence of SDS, color-fading of methylene blue by oxidation with KBrO3 was catalyzed by NO2-, and the sensitivity of the color-fading reaction was found higher than that of the reaction in the absence of SDS. Based on these facts, a micelle-sensitized catalytic spectrophotometric method for determination of trace amount of nitrite was proposed. Linear relationship between the magnitude of decrease in absorbance (ΔA) and mass concentration of nitrite was obtained in the range of 0.02-1.0 mg·L-1, with detection limit (3s/k) of 0.074 mg·L-1. In the determination of trace amount of nitrite in sausage sample by the proposed method, values of recovery found by standard addition method were in the range from 98.8% to 103%, with values of RSD′s (n=5) in the range of 1.9%-2.4%.