This paper is a study of the organization and use of theses collections in university libraries of Korea. A questionnaire consisted of 31 questions on 6 items was sent to 44 university libraries of which 40 libraries responded. Results of the study can be summarized as follows: 1. Figures concerning registration of theses can be tabulated as follows. 2. In differentiation of oriental and occidental theses, 20 libraries (50%) depend on the basis of the text language. 3. Thirty-four libraries (85%) classify the theses and 27 (80%) of them use the same tables with book classification schedules. For classification level, 17 libraries (48.6%) classify them in section numbers whereas 13 (37.1%) in sub-sections. 4. Catalog or index cards of theses are made in 35 libraries (87.5%) of which 20 libraries are using the second level of bibliographic description. 5. Roman alphabets in a title are described a such 27 libraries (67.5%). 6. Most of respondents are preparing author, title and classified catalog cards for users. The research reveals that only 8 libraries are giving subject headings to the theses. 7. Twenty-three libraries (63.9%) have theses catalogs in separation from their book catalogs. 8. Most helpful bibliographic elements in an entry for users are reported to be author, title, date and notes. In general, theses collections have many different features in various aspects compared with book materials. Therefore it is desirable to process the former differently with the latter. Firstly, it would be more convenient to register theses on the different register from the book register. Secondly, minute classification of theses would be necessary for their users. thirdly, text language is the common basis of discriminating oriental materials and occidental ones. Fourthly, a simple catalog would be quite good enough to use theses collection, for most helpful elements in an entry are limited to author, title, date and notes. Fifthly, it is strongly recommendable to transcribe all the roman alphabets on the titles into Korean alphabets. Sixthly, the research revealed that our library would needs to develop subject heading work which is for behind other library works.