The purpose of this study is to examine the effects of utilizing concept maps in a rock-related unit. To do this, two groups composed of 73 sixth grade students engaged in this study. One group (experimental group) participated in utilizing concept maps in the unit, the other (control group) took part in traditional instruction in the same unit. The results of this study are as follows, after seventeen sessions: First, the achievement between the two groups showed significant difference. It indicates that utilizing concept maps as an instructional method is effective. Second, in the examination of the experimental group's attitudes toward concept maps, the students showed more affirmative responses on cognitive items than on affective items. Third, the students showed that they have difficulty in the method and the procedure of drawing up the concept maps. It indicates that the method and the procedure are sufficiently learned before instruction begins.