In this article, Professor Read points out some of the ways in which the adminis trator can judge the science program in his school through a carefully planned pro gram of evaluation. He discusses three basic levels of evaluation in science and indi cates how careful evaluation can help locate unusual science talent among pupils. Turning to sources of evaluation implements, the writer commends evaluation pro grams built up at the local level, and also considers some of the recent endeavors of the College Entrance Examination Board. He points out the importance of testing for problem solving ability and for attitudes related to science. He provides sample items aimed at these two areas of science instruction. The article is concluded with a list of commercial and institutional organizations which distribute secondary-school evaluating materials.