In this study, elementary school teachers' needs for the website providing science instructional materials were examined. The participants were 151 elementary school teachers. The test for needs analysis consisted of fifty-three Likert-type items; 24 items for the content of website category and 29 items for the design of website category. Variables about participants' characteristics such as teaching career, the capability of using computers, and the frequencies of searching websites in obtaining science instructional materials were also examined. The results indicated that teachers' needs for the content of website category were significantly higher than those for the design of website category. Teachers' needs were relatively higher in the items concerning flawless materials, consistency of materials with science curriculum and/or learning objectives, information about target grade and/or related topics, free website, and the materials capable of immediate use in the content of website category. The items concerning the stability of website, the accuracy of links, providing easy and reliable searching methods, easy and fast downloading, and providing list of loaded materials showed relatively higher needs in the design of website category. In several items, teachers' needs were also changed with their individual characteristics.