We have analyzed the effect of light on the steady-state level of the chloroplast elongation factor EF-Tu (tufA) mRNAs during chloroplast biogenesis in rice. The steady-state level of the tufA mRNAs in continuously light-grown seedlings was almost equal to that in the continuously dark-grown seedlings. Furthermore, the tufA transcript level was hardly changed in the transition of dark-grown seedlings to the continuous light and during all chloroplast developmental stages examined. We have previously shownthat light had a similar effect on the tufA mRNA level during chloroplast biogenesis in maize. Therefore, we also examined the possibility of the light-regulation of barley tufA mRNA. It turned out that light had no effect on the barley tufA mRNA level either. Although only three types of grass were examined, these results may show a difference of tufA gene expression between grassess and legumina.