The concentration (in mg kg–1 fresh weight) of two main hydroxamates, 2,4-dihydroxy- 7-methoxy-1,4-benzoxazin-3-one (DIMBOA) and 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA), and their temporal changes were simultaneously investigated using HPLC analysis in the leaves and roots of five Pioneer® maize (Zea mays L.) hybrids to select hybrids with higher hydroxamate contents. Although significant differences were found among hybrids in leaves, youngest leaves and roots, none of them showed unambiguously higher hydroxamate contents. However, the age of the organs and the plants significantly affected hydroxamate content. DIMBOA content of leaves decreased with increasing organ and plant age. DIBOA content varied among the hybrids, but generally decreased in the initial phase and then increased. In the roots, DIMBOA content decreased during the 21-day study and although DIBOA content did not show a clear temporal tendency, differences among hybrids were detected. According to current results, hydroxamate content temporally decreases in hybridspecific patterns, which should be considered when establishing a proper sampling time frame.