This comparative pre-test/post-test quantitative study investigated the effect of an instructional strategy using concept mapping as a graphic organizer on the quality of persuasive writing compositions produced by fourth grade elementary school students. Six fourth grade classes were assigned as intact groups to three conditions: concept mapping treatment, four square treatment, and control. Participants wrote a pre-test essay prior to treatment. Treatment consisted of an instructional unit collaboratively developed by the researcher and classroom teachers on persuasive writing. Instruction for the three treatment groups was the same except for type of graphic organizer used (Concept Map, Four Square, or none). Following treatment, a post-test on persuasive writing was administered in the form of an essay. The concept mapping treatment group used concept mapping as their graphic organizer, the four square treatment group used the four square method, and the control group used no graphic organizer. Each of the pre- and post-test essays for both treatment and control groups were scored using rubrics created collaboratively by the researcher and participating teachers for Persuasive Content and for Engagement with Content. Only the concept mapping treatment group created concept maps during the post-test. Therefore, only the concept mapping treatment groups' essays received a score for Sophistication of the Concept Map. One-way Analysis of Variance showed a significant mean difference in Persuasive Content and Engagement with Content between the three treatment groups. Concept Mapping had the highest mean scores on each, followed by Four Square and then the control. Pearson's product-moment correlation showed a moderate positive correlation between Sophistication of Concept Map and both Persuasive Content and Engagement with Content. Positive correlations were also found between prior KCCT scores and persuasive writing scores and prior writing portfolio scores and persuasive writing scores. No significant correlation was found between gender and persuasive writing scores or race/ethnicity and persuasive writing scores. The results of this study indicate that Concept Mapping improves Persuasive Content and Engagement with Content when used as a graphic organizer in the writing of persuasive essays. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]