A preliminary analysis was published in 1993 of 100 cases of endoscopic sinus surgery (ESS) carried out in our service following a protocol that included sinusitis, nasal polyps, and other endoscopic nasal procedures. Another 100 cases of ESS were analyzed for the present study and compared with the 1993 group. Comparative analysis showed improved results in the second series, with fewer minor complications and no major complications. These findings confirm the general opinion that endoscopic sinus surgery requires an adequate training period before optimal results are obtained.