An instructional unit was developed to enhance the critical thinking skills of middle school and high school students with learning disabilities by teaching them the principles of scientific reasoning. Student-teacher dialogues were used to engage the students in an active process of critical inquiry. Students analyzed everyday information presented in brief magazine articles and advertisements by applying the principles of the scientific method. The students made statistically significant improvements in their ability to (a) identify the principal claim made in an article or advertisement, (b) graph the relevant data, and (c) evaluate the claims made in the article and explain their support or rejection of the claims based on data. After the instructional unit, the overall performance of the special education students exceeded that of a control group composed of regular education students who had not received instruction in critical thinking.