We investigated the uptake and distribution of zinc (Zn) either applied to the roots or to the leaves in rice during grain development. Plants of two aerobic rice cultivars were grown in a nutrient solution with either sufficient Zn or surplus Zn. Root treatment with 1 week's supply of both 65 Zn and unlabelled Zn was started at flowering or 15 days after flowering (DAF). Foliar treatment with 65 Zn applied to the flag leaf or to senescent leaves was carried out at flowering. When 65 Zn was applied to roots, plants continued to take up Zn after flowering, even beyond 15 DAF, irrespective of cultivar and Zn nutritional status of the plants. During the 1 week of supply of both 65 Zn and unlabelled Zn, which either started at flowering or 15 DAF, the absorbed 65 Zn was mainly distributed to roots, stem and grains. Little 65 Zn was allocated to the leaves. Following a week of 65 Zn supply directly after flowering, under sufficient Zn or surplus Zn, the proportions of total 65 Zn uptake allocated to the grains continued to change during grain filling (9-33%). This Zn mainly came from the roots but under sufficient Zn supply also from the stem. With 65 Zn applied to leaves (either the flag leaf or the lowest senescent leaf), both cultivars showed similar Zn distribution within the plants. About 45-50% of the 65 Zn absorbed was transported out of the 65 Zn-treated leaf. From that Zn, more than 90% was translocated to other vegetative organs; little was partitioned to the panicle parts and even less to the grains. These results suggest that in rice plants grown under sufficient or surplus Zn supply, most of the Zn accumulated in the grains originates from uptake by roots after flowering and not from Zn remobilisation from leaves.