Commercial edible soybean oil was introduced into plastic containers. Colorless transparent (control), red transparent, green transparent cellophane films and, also, colorless transparent cellophane films coated respectively with Cemedine C, Cemedine C containing 10% pyridine, benzophenone, and p-aminobenzoic acid were prepared, and the % transmittance of each film to lights at U.V. and visible regions were measured. The containers were covered with the films and irradiated simultaneously with direct sunlight for 4.5 hours daily. The peroxide values of the oils in the plastic containers were determined at regular intervals. The effects of the Alms on the PV development of the oils were compared with that of the control, i.e., the colorless transparent films.The red and green films showed strong retarding effects ell the PV development. The red films showed a slightly stronger effect than the green ones. The colorless transparent films coated with Cemedine C showed an appreciable retarding effect. The films had absorbed the lights at the U.V. and visible regions considerably. The pyridine and benzophenone coated films lost their retarding effects after 10 and 4 days respectively. The p- aminobenzoic acid coated films showed a considerable retarding effect throughout the experimental period. The films had absorbed the lights strongly .As a whole, the retarding effects of the films on the PV development were, in decreasing order. as follows; Red> Green> p-Aminobenzoic acid coated > Cemedine Ccoated) Control > Pyridine coated > Benz ophenone coated