Vitamin contents of three grades of Korean laver high, medium and low were measured. They were cooked by different methods to examine changes in their vitamin content. Results of this experiment are as follows ; 1. Vitamin contained in loogr of laver amount to 13,200 I.U, for high grade, 16,100 for mediium grade, and 16,400 for low grade . The low -grade laver, which is interwoven with green laver, showed the highest vitamin content. 2. When laver was broiled sheet by sheet, its vitamin loss rate was 11% for high grade, 19% for medium grade, and 20% for low grade. Thus , the one with a higher vitamin content showed a higher vitamin loss rate. When two sheets of laver, which were put upon each other, were broiled, their vitamin loss rates were 2.3% for high grade, 1.73 % for medium grade, and 2.64% for low grade. Thus broiling laver at the unitof two to three sheets together is a way of decreasing the vitamin loss rate. 3. When laver was broiled with salt applied on its surface , its vitamin loss rate was 8.3% for high grade, 13% for medium grade, and 10.9% for low grade. When laver was broied at the unit of two sheets together after salt and sesame oil were added, its vitamin loss rate was 2.2% for high grade, 5.2% for medium grade, and 8.2% for low grade . The one with a higher vitamin content showed a higher vitamin loss rate. 4. When laver was mixed seasoned soysauce, its vitamin loss rate increased in process of time. In 48 hours after laver was mixed with seasoned soysauce , its vitamin loss rate read 24.2%, 27.1% and 35% respectively, for the three grades of laver. Thus the laver mixed with seasoned soysauce has to be used right after so cooked so as to obtained the highest possible vitamin content.