The psbA gene of photo system II was cloned and characterized from the P. ginseng chloroplast. The psbA gene is composed of 1,062 nucleotides. The overall amino acid sequence shows 99% and 98% identities to dicots and monocots of higher plants, respectively. Southern blot analysis revealed that a single copy of the psbA gene existed in the chloroplast genome. Northern blot analysis of the in vivo accumulation of the psbA transcript, after being grown under the different intensities (5%, 10%, 20%, and 100%) of daylight, indicated that the steady-state level of the psbA transcript was not significantly affected by light intensity.