A review of the literature indicated that some studies had investigated the effects of light on learning, but that learning style preferences for bright or low light had not been studied in relation to academic achievement. This relationship was studied with fourth-graders in a suburban school in New York State. Students took the Learning Styles Inventory of R. Dunn and others (1979) to indicate their preferences for concentrating in bright or dimly lit areas. Thirty-two of the students tested revealed extreme preferences for one condition or the other (approximately 9% of the total population of fourth-graders in the district). These 32 students were tested for reading speed and accuracy on a standardized test in an extremely bright and then in an extremely dim instructional setting. Scores on both speed and accuracy were considerably better when the environment matched the student's diagnosed learning style preferences for light. The results are discussed in terms of their implications for classroom illumination and the influence of light on human mood. There are 49 references. (SLD)