Twelve patients with chronic sinusitis were treated with classical sinusectomy and eight with antrostomy using the Nd-YAG-LASER technique. In the Iatter group, normal sinus mucosa was well retained and the natural ostium was widely opened by Nd-YAG-LASER. All patients received antral irrigation for 3-4 days after surgery. Seven ofthe l2 patients treated with classical sinusectomy had Ps. aeruginosa infection at the site of operation, while no sinus infection was found in the eight patients with Nd-YAG-LASER antrostomy except in one case in which intensive LASER vaporization of pathological sinus mucosa was performed. Sinus drainage after Nd-YAG-LASER antrostomy appears to be much better than after classical sinusectomy, because mucocilliary clearance plays an important role in the prevention of bacterial infection