Introduction : Writing the thesis is one of the first experiences of university students. It is usually conducted satisfactorily under the advice an advisor. Yet, there are some problems in this regard.

Objectives : The purpose of the present study was to evaluate the quality of the medical and dental theses at Shahid Sadoughi University of Medical Sciences.

Methods and Materials : This was a qualitative observational study conducted on 30% of medical theses and all the dental theses at Shahid Sadoughi University of Medical Sciences during 1992-2002. The characteristics and features of the different parts of the theses were recorded in a questionnaire. Then, the quality score was calculated for each thesis.

Results : In this study, 215 (76.2%) volumes of theses of medical students and 67 (23.8%) volumes of theses of dentistry students were studied and reviewed. Most of the theses studied (13.8%) related to internal medicine, and least of them (1.8%) related to pathology. The majority of the theses (92.7%) were of experimental research type, and 2.5% included case studies.95.7% of the theses were appropriate regarding title characteristics. Almost 19% of them lacked the part "Statement of the Problem" and 43.2% were deficient in this part. 40.7% of the theses (52% of medical theses and 6% of dental theses) lacked "Review of Literature". Only 51.6% of them (40.7% of medical theses and 86.4% of dental theses) possessed a "Review of Literature" that was quite related to the thesis topic. In approximately 5.8% of the theses, there was no direct reference to the objectives. For 12.4% of theses, the objectives have been stated accurately while for 81.8% of them this was not the case. Regarding objectives, the medical theses were in a better state and showed a statistically significant correlation with the dental theses. Regarding the part "Results", in 6.9% of the theses, specific objectives have not been stated clearly. 82.6% reached completely to the preset goals, 9.1% achieved some of the objectives, and 1.4% of results were irrelevant to the objectives.

Regarding the presentation of thesis results as an article in magazines or in national or international gatherings, summits, conferences, or a congress, 1.1% were presented in conferences abroad, 9.6% in national seminars, and 28.8% as an article. Also, 46.3% were not published at all. For 14.2% of the theses, no information was available regarding their publication. The average mean of the number of references was 21.8. Also, 6.6% of the references were 3 years older than the thesis. Four references were 4-5 years older than the thesis and twelve references were more than 5 years older than the thesis. Totally, the average mean of time interval between the thesis and the references publication date was 5.8 years. Generally speaking, 14.9% of the theses had a poor quality, 44.35 had a moderate quality, and 4.8 % possessed a high quality. In this regard, the dental theses had a better status. There was no statistically significant correlation between thesis quality and the obtained score on the thesis.

Conclusion : Considerable percent of theses had weak quality, but dentistry students' theses had the better quality than the medical students' theses. Therefore, to improvement of thesis quality, it's necessary to carry out various workshops on the research methodology, scientific article writing and writing reports.