Considering the importance of medicine and the ever-increasing developments in medical research, the implementation of such research according to the ethical principles and criteria of creditable national and international declarations is of great significance. According to these declarations, the researcher has the highest responsibility to observe the rights and safety of participants. The present study intends to survey the rate of observance of research ethics in proposals approved at Urmia University of Medical Sciences between the years 2003 and 2008. Three hundred and twenty four research proposals that had been approved between 2003 and 2008 were evaluated retrospectively. Related checklists (self- constructed ones and World Health Organization checklists) were completed for each project, a statistical analysis of the results was done by SPSS software, and descriptive statistics were subsequently extracted.  A summary of the most important results is as follows: In 85.5% of the proposals, the ethical considerations part was completed. In 68.4% of the cases the participants were aware of participating in the study and in 67.9% of the cases the informed consent of participants was obtained, 50.9% of which was in written form. Among clinical trials, in 80% of the proposals informed consent was obtained, 85% of which was written. Out of 60 clinical trials, 37 projects (62%) were confirmed by the ethics committee. Considering the results obtained in this study, principles of research ethics were applied more closely in this study compared to similar studies in Iran. It seems this is due to the establishment and launch of regional ethics committees in 2003 and afterwards. However, in order to bring these measures closer to current standards, holding educational workshops for honorable members of scientific boards and students is recommended. Moreover, more accurate supervision of ethics committees, especially in clinical trials and animal experimentations, seems to be beneficial.