The subjective aspects of map-to-reader communication have begun to receive increasing attention from cartographers, but a suitable method for measuring reader attitudes toward maps has been elusive. In this study, the semantic differential technique was used to gauge reactions of subjects to a variety of thematic maps. The test proved to be sensitive to different design characteristics of the maps, and factor analysis of the results produced three factors by which the maps appeared to be judged, reflecting in part the choice of adjective pairs comprising the test.