Soybean seeds (Glycine max (L.) Merrill) of Santa Rosa cultivar, collected in two different cropping areas, were used in a research project designed to study soybean seed maturation. The experimental part of this research was conducted at the Horticulture and Agriculture Department of the Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo, Brasil. Seed quality of each lot was evaluated by means of germination test. Plant development and seed maturation were studied in a completely randomized split-plot field experiment planted in November of 1977; seeds of the two lots were planted so as to assure stand uniformity among the experimental plots. Beginnirig of flowereing and fruiting were dated by countíng the plants that had at least one flower or fruit raceme, respectively. The seed were harvested seven times. After each harvest the following data were obtained; moisture content, dry weight, tegument and hilum color (Munsell system), germination and vigor of seeds. The analysis and interpretation of data allowed for the conclusion that a near match founded soybean physiological maturity and absence of yellow-green seeds with homochrome hilum. On the other hand, maximum soybean seed dry weight was considered to the insufficient by itself to characterize physiological maturity.