This study analyses the citations of Masters Theses on Sociology at the University of Peradeniya submitted from 1995 to 2012 to determine the format and age of materials used and most frequently cited journals. The citation analysis method was used as the data collection method and the citations were extracted from the title pages and reference lists of each of the theses. Data obtained from 12 masters theses were examined in June, 2013. The study found that 56% of cited items were monographs followed by 22% were journals, 8.5% were reports, 4% were web resources and 3.7% were conference proceedings. This is contrary with other citation analysis, which found that journals are the most frequently used format. The study also revealed that nine journal titles are the most frequently cited journals by sociology graduates. The study indicated that the average age of materials used was 10-20 years. The findings and implications of the research for collection development have been discussed. This study could serve as a collection development tool that can be used as a model for the library to identify the primary sources for acquisitions and also as a guide for collection maintenance.