In order to know the influcncc of fertilizer and planting density on the chemical composition of soybean seeds, 2 kinds of field experiment were performed on 2 varieties and 2 lines in 1975 and 2 varieties and 1 line in 1976 at Hokkaido Prefectural Central Agricultural Experiment Station (Experiment 1) and on 3 varieties and 9 lines in 1975 at Hokkaido Prefectural Tokachi Agricultural Experiment Station (Experiment 2). Among the varied fertilizer conditions, significant difference was not observed in experiment 1 and 2. On the planting density, close planting significantly increased protein content and significantly decreascd oil, carbohydrate, and ash content in experiment 1. On the other hand, significant differene was only observed on ash content in experiment 2. The varieties in experiment 1 and 2 differed significantly on all chemical compositions. On the significant interactions, there were fertilizer × planting density on ash content, density × variety on protein and ash content, and fertilizcr × variety on oil, carbohydrate, and ash content in l975 (Experiment 1), and variety × density and fertilizer × density on ash content (Experiment 2). On the correlation between chemical component content and growth habit, weight of 100 seeds or yield, protein content was positively correlated with the length of main stem, weight of 100 seeds or yield, and negatively with the number of branches per plant or number of ripe pods per plant. Oil, carbohydrate, and ash content was positively correlated with number of branches per plant or number of ripe pods per plant, and negatively with length of main stem, weight of 100 seeds, or yield.