This research was one part of the whale .research which have been designed far the purpose of investigating korean high school students` misconceptions on biology. As previously reported by Chung et al.(1992), korean biology teachers stated that korean students had many biological misconceptions. The previous study was a pilot study of this study. This study was to identify high school students` misconceptions about reproduction and development of organism. For this study, a free-answer form questionnaire consisted of twenty-one items, was specially developed through analysis of high school biology curriculum shout reproduction and development, developed and sent to fifty four high school students lived in Seoul. Their responses were collected and analyzed qualitatively. The results of the analysis of the students` responses will be used essential data for the following questionnaire development.