Soybean varieties Kaohsiung No. 3 (KS 3) and Shih-Shih (SS) were grown in the summer (1981) and spring (1982) crop seasons to study the amounts of TNC, N, F, K and Mg accumulated by different plant organs during successive developmental stages. Between V3 and R5 stages, leaf blade was the organ of predominant nutrient accumulation and the amounts accumulated by the whole plant and various vegetative organs were greater for the spring than for the summer crop. Pod wall and seed were the major organs of nutrient deposition during seed-filling. The amounts of TNC and mineral nutrients accumulated in the reproductive organs as well as in the whole plant were higher for the summer crop during the same period. The maximum amounts of nutrients accumulated by soybean crop were 120-270 kg N/ha, 27-44 kg P/ha, 70-130 kg K/ha and 15-30 kg Mg/ha. The accumulation rates (kg/ha/day) by the whole plant during rapid seed-filling were N: 3-8, P: 0.3-1.2, K: 1.4-3.8 and Mg: 0.3-0.8; whereas the rates by the seed were N: 4.4-12.9, P: 0.7-1.7, K: 1.8-2.6 and Mg: 0.3-0.5. These results indicated significant retranslocation of N and P from vegetative organs to the developing seeds. TNC/N ratio in the pod wall increased markedly during seed-filling and was significantly higher for the summer than for the spring crop. On the contrary, TNC/N ratio in the seed showed a decreasing tendency during the same period. It was also slightly higher for the summer crop. Poor ability of TNC production was suggested as one of the factors for the low grain yield of soybeans grown in the spring crop season.