---

Background and Objective: Quality of medical articles is effective at improvement of medical science. This study was done for determining of published medical articles quality in approved Medical Journals. Materials and Methods: This cross- sectional study was done on 690 medial articles, which published between 1983-2005 in scientific journals, approved by special Medical Journal committee of Ministry of health and medical Education (MOHME) in Iran, during 2007. Source of data was indexed medical journal in the Iranmedex database. Results: Type of study in 52% of articles was descriptive, 21.2% was interventional and 5.8% of them were analytical. In recent years the number of analytic and interventional articles have been increased significantly in comparison to other types (P<0.05). There was no qualitative type article in published papers. The percentages of original, case report and review articles were 44.9%, 36.9% and 14.1%, respectively. In recent years the rate of original articles has increased in comparison to case report and review articles (P<0.05). In 80% of articles, at least one statistical test was applied. 60% of articles were clinical and 82% of them have been written in Persian language. Conclusion: Findings showed an increasing trend in quality indexes of published articles. It seems in recent years, the changes of MOHME policies in evaluation of the research deputy of medical science universities implementation of research and scientific writing workshops ratting protocol of approved medical journals and academic members promotion guidelines, resulted in improvement qualitative index of articles.