A study investigated the effectiveness of using thematic organizers to increase the reading comprehension of poor readers. The thematic organizer was used to expand the readers' prior knowledge by defining the implied thematic concept and presenting relevant examples of that concept. Twenty-four fourth, fifth, and sixth grade students who had been classified as below-average readers were assigned to one of two remedial reading tutorial groups. The tutors for these groups used the same teaching script with the following exception: tutors in the experimental condition used a thematic organizer with their reading assignments, while tutors in the comparison group used a set of prereading questions. Analyses of pretest and posttest comprehension scores showed that the students in the experimental group performed significantly better than the students in the comparison group on literal retellings, inferential retellings, literal recall questions, and inferential questions. The experimental group also recalled more of the most important idea units and more complete propositions (preserving the meaning of the original passage units) than did the comparison group. (RL)