It is of interest to elucidate the change of the content of these metabolites of IAA contained in corn kernels, especially from differences among cultivars and stages of development. The change of content of these IAA-related compounds in corn kernels may afford useful information about IAA metabolism. This paper describes the change of content of V, VI, VII and VIII contained in corn kernels of four cultivars at different stages of development. Kernels of sweet corn (cv. Golden Cross Bantam and cv. Honey Bantam) and dent corn (cv. Pioneer dent corn and cv. White dent corn) were harvested at various development stages, and the IAArelated metabolites were analyzed quantitatively by HPLC. Metabolites 7-0-P-D-glucopyranosyI3,7 dihydroxy-2-indolinone-3-acetic acid (zeanoside A and C), 8-0-p-D-glucopyranosyl 8-hydroxy-2 quino1one-4-carboxylic acid (zeanoside B) and 8-hydroxy-2-quinolone-4-carboxylic acid (zeanic acid) were found in the corn kernels. The content of zeanoside A and C in the corn kernels increased markedly at 20 ~ 30 days after silking, and then gradually decreased as the kernels matured. The content of zeanoside B in the corn kernels was highest in the early stages and disappeared at 20 ~ 35 days after silking. Content of zeanic acid remained more or less unchanged at all development stages of the corn kernels.