The purpose of this study is to examine the effect of creative drama-based instruction on seventh graders' science achievements in the ecology and matter cycles unit and their attitudes toward science. The study is an experimental study carried out in one of the public elementary schools in Turkey during 2005-2006 schooling year. An ecological concept achievement test was developed and administered to 45 students in two classes (as control and experimental group) of an elementary school before and after the treatment. The experimental group received creative drama-based instruction and the control group received traditional instruction. A guiding instruction material which contains six lesson plans in the subject was constructed for the teacher to administer creative drama-based instruction. The topics of ecosystems and matter cycles were taught to the both of groups for 3 weeks. A science attitude test was administered to both groups before and after the treatment. The results revealed a statistically significant difference between the mean scores of the both groups with respect to achievement in the ecology concepts and median of the attitudes toward science in favour of the experimental group after the treatment.