Increased attention has been directed at the quality of randomized controlled trials (RCTs) and how they are being reported. We examined leading anesthesiology journals to identify if there were specific areas for improvement in the design and analysis of published clinical studies. All RCTs that appeared between January 2000 and December 2000 in leading anesthesiology journals (Anesthesiology,Anesthesia & Analgesia,Anaesthesia, and Canadian Journal of Anaesthesia) were retrieved by a MEDLINE search. We used a previously validated assessment tool, including 14 items associated with study quality, to determine a quality score for each article. The overall mean weighted quality score was 44% +/- 16%. Overall average scores were relatively high for appropriate controls (77% +/- 7%) and discussions of side effects (67% +/- 6%). Scores were very low for randomization blinding (5% +/- 2%), blinding observers to results (1% +/- 1%), and post-beta estimates (16% +/- 13%). Important pretreatment clinical predictors were absent in 32% of all studies. Significant improvement in the reporting and conduct of RCTs is required and should focus on randomization methodology, the blinding of investigators, and sample size estimates. Repeat assessments of the literature may improve the adoption of guidelines for the improvement of the quality of randomized controlled trials.