This article reports the results of a content analysis of Masters dissertations of four branches of the Islamic Azad University in the field of Library and Information Science (LIS). The four branches were: North Tehran branch, Tehran's Science and Research branch, Ahvaz's Science and Research branch, and Hamadan branch. The aim of the study was to find out about the subject trends of the dissertations during 1993-2007 periods, as well as to show the distribution of the dissertations with regard to the year of writing, gender, number of pages, research methodology, and references. In total, 524 dissertations were examined. The results showed that the average number of pages was 107-137, about two third of the dissertations were written by female students, and survey was the most used research method. Questionnaire was the most used tool for data collection. Persian language resources accounted for about 70.06 percent of the references of the dissertations. The most popular subject for the dissertations was ‘libraries and information centers’ and the least popular subject was ‘preservation of library material’.