We performed a systematic review assessing the reporting quality of trials of surgical interventions, and explored associated trial level variables. Randomized controlled trials (RCTs) provide clinicians with the best evidence for the effects of interventions, but may not be reported with necessary detail. In May 2009, 3 databases (MEDLINE, EMBASE, and CENTRAL) were searched for RCTs that assessed a surgical intervention using a comprehensive electronic strategy developed by the Cochrane Collaboration. The Consolidated Standards of Reporting Trials (CONSORT) checklist was used as a measure of reporting quality. An overall CONSORT score was calculated and expressed as a proportion. This was supplemented with domains related to external validity. We also collected data on characteristics hypothesized to improve reporting quality, and exploratory regression was performed to determine associations. One hundred fifty recently published RCTs were included. The most commonly represented surgical subspecialties were general (29%), orthopedic (23%), and cardiothoracic (13%). Most (65%) were published in subspecialty surgical journals. Overall reporting quality was low, with only 55% of CONSORT items addressed. Less than half of trials described adequate methods for sample size calculation (45%), random sequence generation (43%), allocation concealment (45%), and blinding (37%). The strongest associations with reporting quality were adequate methods related to methodological domains, an author with an epidemiology/statistics degree, and a longer report length. There remains much room for improvement for the reporting of surgical intervention trials. Authors and journal editors should apply existing reporting guidelines, and guidelines specific to the reporting of surgical interventions should be developed.