Artículo de publicación ISIObjective: To evaluate the reporting quality of key methodological items of randomized control trials (RCTs) in 55 of the highest ranked journals. Study Design and Setting: A list of the highest top ranked journals was identified, and a search for detecting RCTs in those journals was made. Two hundred sixty four journals were screened and 55 of them were identified having at least one RCT. Three RCTs were randomly selected a priori from each journal; 148 RCTs were finally included. RCTs were assessed by two reviewers using the Consolidated Standards of Reporting Trials (CONSORT) statement. Results: Only 11 (8%) RCTs had all items adequately reported. In addition, 36% of RCTs reported that the study was registered in any trial registry. We found a significant difference in the quality of reporting for baseline characteristics, recruitment, participant's flow, and randomization implementation between those studies having reported the registration of their RCT in a trial registry and those that have not. Adherence to key methodological items of the CONSORT statement was as follows: sample size determination (60%), sequence generation (49%), allocation concealment (40%), and blinding (25%). Conclusions: Reporting of varied CONSORT items remains suboptimal. Registration in a trial registry was associated with improved reporting. Further efforts to enhance RCT registration could contribute to this improvement.