Involvement of active oxygen species in the accumulation of early light-inducible protein (ELIP) in mature pea plants was investigated under light stress conditions. Here we provide evidence th at hydroxyl radicals and singlet oxygen interfere with ELIP expression at both, transcriptional and posttranslational levels. Addition of free radical scavengers can alleviate the detrimental action of the radicals almost completely at the level of transcription but only a partial protection was observed at the level of proteins. The data suggest that the damage of ELIP occurs during its insertion into thylakoid membranes close to the free radical sources.