The biology textbooks, including eight for Science I and six for Biology, currently using in Korean high schools were examined for mistakes, especially in the plant part. As a result, four mistakes in the figures and three mistakes in the text were found. The mistakes in the figures include figures of Psilotum nudum (L.) Griseb. and Fragaria chiloensis var. ananassa Bailey, and the stigma morphology of Oryza sativa L. The mistakes in the text were the genetic characters used by Mendel in Science I textbooks, and the explanations of the scientific name and the concepts of seed plants in Biology textbooks.