The aim of this study was to compare the incidence of complications of endoscopic sinus surgery (ESS) to the incidence of complications of traditional and microscopic sinus surgery. A meta-analysis was carried out on 28 series of patients (a total of 13,405) who had undergone ESS, 8 series of patients (3,887 in total) who had undergone traditional endonasal sinus surgery and 7 series of patients (1,630 in total) who had undergone microscopic sinus surgery. The authors used the Bayesian inference package WinBUGS operating from within the statistical computer program R (version 2.7.1). Major complications had a higher incidence after traditional sinus surgery than ESS but this fact did not cause a significant statistical difference, whereas microscopic surgery had significantly more complications than ESS (p < 0.05). Carrying out our meta-analytic study, comparing major and minor complications of endonasal surgical approaches, was very difficult due to several methodological biases of data extraction and evaluation from studies concerning a broad timespan. Regarding major complications, we only found a significant statistical difference (p < 0.05) between the endoscopic (1%) and the microscopic methods (2.0%), but, if we had analyzed the data considering the natural learning curve of the latest ESS surgical approach, and if we had not considered the results produced in the first 10 years (1988-1998) concerning ESS in our meta-analysis, we would have found a statistically significant difference (p < 0.05) between the endoscopic (0.4%) and the traditional (1.1%) approach as well.