Background and Aim: These days, Internet and online databases play a significant role in peoples’ information-seeking behavior, especially for postgraduate students. The kind of behavior seen on the part of those students who get help from online databases to write their theses might be completely different from those who search library sources to get the needed information. This study investigates the information-seeking behavior of postgraduate students of Kharazmi University who are writing their theses.

Method: This study used both qualitative and quantitative methods of data collection. Quantitative data were gathered using an information-seeking behavior questionnaire, which was then, analyzed using statistical analysis (T-Test and Friedman-Test). Content analysis and semi-structured interviews were used to analyze qualitative data. The participants were 100 students including 50 male and 50 female students.

Results: Results of analyzing the T-Test for male and female groups showed that there is not any significant difference of girls' and boys' information-seeking behavior. Results of analyzing the Friedman-Test however showed difference in average ratings of information-seeking behavior dimensions. With regard to results obtained from this analysis: pre-existing knowledge confirmation, relevancy judgments, bringing up new thoughts, time and effort for searching information contain maximum to minimum rates in a respective manner. Results of the qualitative data also showed that: most of the students’ problems lie in: seeking for and using the collaborative behavior and collaborative searching, difficulty in finding the related information, language limitations, diversity of goals, limitations the forms of the sources, unfamiliarity with the specific sources, lack of information literacy, and spending so much time to search.

Conclusion: Findings obtained in this study showed that postgraduate students do not have the skills and knowledge needed for using online data. This also indicates their deficiency and lack of information seeking and information literacy skills. So, recognizing the obstacles on the way of knowing and using these online databases and training students for purposeful searching seem to be essential.