Introduction: Abstract writing is one of the secondary services for summarizing the content of documents. It represents the major information and is used as an overview of the text. However, abstracts should be written and indexed on the basis of some criteria to provide sufficient and reliable information about the main text. This study aimed to assess the abstracts of Randomized Controlled Clinical Trials (RCTs) indexed in PubMed on the basis of the CONSORT abstract checklist.

  Methods: This was a descriptive cross-sectional survey. The study sample included 314 RCTs indexed in PubMed with the affiliation of Iran and Tehran University of Medical Sciences up to the end of 2010. The abstracts were evaluated by the CONSORT checklist in which the items were scored 0–8 .

  Results : The Mean score for quality was 4.7± 1.02 out of 8 . None of the abstracts were assigned as the most qualified (Score=8) and the highest score was 7. Among the RCT designs, parallel trial designs were the most common ones. Indications of the type of randomization, the blinding type, and the number of participants involved were found not to be well reported qualitatively.

  Conclusion: The findings indicated that the items designated for RCTs abstracts were not thoroughly taken into consideration. It seems that training of researchers and authors is required for betterment of the quality of reporting in abstracts. In addition, journal editors should provide guidelines for authors to report this type of studies correctly.