The study is aimed at assessing the effects of households' land use after the implementation of the farm land accumulationin two sub-regions of Nam Dinh province via indicators of economic and social efficiency. Mer that the calculates aggregate efficiency (Ect) is calculated to propose the right area fpr agricultural land. The findings of the study show that households have carried out the accumulation basing on 3 major forms (tender, lease or land-using rights transfer) with 4 scales and 4 types of land use. In addition, the calculation shows that for the type of using 2 rice, 2 rice - annual crops, and aquaculture, the larger the agricultural land is, the greater the efficiency becomes apart from the land for general livestock raising. The sustainability of land using efficiency requires the maintenance of agricultural land which is large enough for each LUT as follows: LUT 2 riceis for QM3 and QM4 (Eet 0.8); LUT 2 rice - annual crops is for QM2 (TV1), QM3 (IV2); LUT aquaculture is QM3 and QM4 (Ect 0.9). Moreover, comprehensive solutions are needed to enhance the local production development.