We assessed abstracts of the IXth Congress of the Middle East Society for Organ Transplantation (MESOT) (December 6-10, 2004, Ankara, Turkey). Assessment was done with a valid and reliable 19- items quality assessment checklist which was developed by Timmer et al (2003) with a good inter-rater agreement (intra class coefficient 0.61-0.81). From the total 396 Congress abstracts, cluster random sampling was applied to select abstracts from and poster presentations. We assessed 109 abstracts, by recording presentation type, study type, country of study, number of authors and transplantation type, and we also assessed study, design and final quality score for each sample. Evaluation of the abstracts was performed by a single methodologist investigator. The mean (SD) quality score of all abstracts was 0.60 ± 0.11 (range: 0.33-0.81), and more than %80 had a score above 0.50. Human observational studies had higher scores compared to human and basic interventional studies (P=0.001). Other variables had no association with quality scores. The strongest parts of abstracts were appropriateness of subjects and sufficient description of study objects, with a mean score of 0.97 and 0.91, respectively. For common items, characteristic of subjects (average score 0.45), method of their selection (average score 0.46) and sufficient detail of results (average score 0.55) were the weakest parts of abstracts. Overall, the quality of the abstracts presented in IXth MESOT congress was acceptable. However, according to our study, a better description of subjects, method of subject selection and detailed report of the results are certain aspects which could be taken into consideration.