In the Mekong Delta of Vietnam, rice (Oryza sativa, L.) is usually planted two to three times annually.  Limited evidence elsewhere suggests that rice crop uptake of soil N under such intensive cropping can be increased by replacing the customary anaerobic decomposition of crop residues with aerobic decomposition.  In this screenhouse study, crop residues were incorporated into three potted Delta soils and allowed to decompose for two to four weeks under either aerobic or anaerobic conditions.  In the following rice crop, grain yield increased for the three soils by 11, 13, and 37% with 2-wk drying compared to anaerobic decomposition and by 19, 35, and 69% with 4-wk drying.  Crop N uptake provided analogous increases: 14, 31, and 63% for 2-wk drying and 3, 48, and 96% with 4-wk drying.  The increase in N uptake involved mostly soil N, not fertilizer N.  The quantities of labile humic acid fractions that were extracted from the three soils were 6 to 31% less with aerobic decomposition than with anaerobic decomposition.  These results suggest that aerobic decomposition of crop residues promoted mineralization and crop uptake of soil N.