The Oregon State University Library currently assigns Library of Congress subject headings to OSU master's theses and doctoral dissertations. A study was undertaken to determine if this activity is warranted. Two surveys were conducted to learn about the usage of these materials and whether other methods of providing subject access would be advisable. The findings showed that graduate students were the primary users. The major reasons were general research and research for individual theses and dissertations. There were no significant differences in searching patterns between general materials and theses or dissertations. We concluded that full subject analysis remains necessary for effective retrieval.