Seven-day-old rice seedlings ( Oryza sativa L. cv. Kinuhikari) were subjected to anaerobic stress and their proteins were analyzed using SDS-polyacrylamide gel electrophoresis. Anaerobic stress caused only minor changes in the pattern of proteins in the shoots, but disappearance of many protein bands in the roots. Three anaerobic stress proteins (ANPs ; 36-, 40- and 87-kD protein) were selectively induced in both roots and shoots of the seedlings, and 36-kD ANP was identified as the glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by limited N-terminal amino acid sequencing. Activities of GAPDH in the shoots and roots were increased by the stress for over 24 h, and were 3.4- and 6.2-fold greater than those in non-stressed seedlings at 24 h, respectively. These results suggest that anaerobiosis induces the production of ANPs including GAPDH in the seedlings, which may allow the seedlings to survive under the stress condition.