Aim is to determine the efficacy and pain level associated with the use of dissolvable carboxymethyl cellulose (CMC) foam dressing in functional endoscopic sinus surgery (FESS) in adult patients. In the present prospective study, 60 patients with bilateral chronic rhinosinusitis were included. All patients underwent bilateral FESS. Thirty patients had both nasal cavities packed with dissolvable CMC foam (CMCF) and another 30 patients had their nasal cavities packed with routine nasal packing (RNP) in latex glove fingers. The haemostatic effect of the CMCF was assessed during the recovery period, and pain levels were recorded by the patients on a visual analogue scale 24 h after surgery. The prevalence of postoperative middle meatal synechia formation was assessed 1, 2, 4 and 8 weeks after the operation. Four (13.3%) of the patients packed with CMCF had primary postoperative bleeding during the recovery period and required additional dressing. Bleeding appeared in two (6.7%) patients packed with RNP. The mean level of pain was 0.962 (range 0-4) for patients packed with CMCF but was 5.5 (range 3-9) for patients packed with RNP. Four (6.7%) of 26 CMCF patients and 10 (35.7%) of 28 RNP patients developed a synechia in the middle meatus. We found that dissolvable CMC foam dressing is associated with very low levels of localised pain and with low levels of postoperative bleeding and synechia formation.