BACKGROUND Paranasal sinus mucocoele is a benign pseudocystic lesion, which may originate from any sinus cavities when their natural ostia are blocked. Raising mucocoele in frontal, ethmoid or sphenoid sinus causes headache, disorders of eye mobility and deformities of forehead or orbit. OBJECTIVE was clinical analysis of treatment results taking into consideration the method of surgical treatment. METHODS Presented material consists of 42 patients (39 adults and 3 children), 22 females and 20 males, in the age from 8 to 76 treated at Department of Otolaryngology of Medical University of Gdansk in the years from 1995 to 2005 for paranasal sinuses mucocoele. RESULTS Fronto-ethomidal mucocoele was found in 22 (52.4%) patients, ethmoidal--in 10 (23.8%), frontal--in 4 (9.5%), spheno-ethmoidal--in 4 (9.5%) and maxillar in 2 (4.8%) patients. 14 (33.3%) cases were primary and 28 (66.7%) secondary of mucocoeles. The most frequent symptoms of frontal or ethmoidal mucocoele were: headache, lacrimation, deformity of orbit, blepharoedema, and diplopia. Sphenoethmoidal and maxillar mucocoele caused mostly nose obstruction and severe headache. Destruction of sinuses and orbital bony wall was found in 16 patients (38.1%), and in 9 of them (21.4%) there were in medial wall of orbit, in 3 (7.1%)--in inferior wall of frontal sinus, in 3 (7.1%)--in anterior wall of frontal sinus, and in 1 (2.3%) in anterior wall of maxillary sinus. In 3 patients (97.1%) with fronto-ethmoidal mucocoele as the consequence of disease the development of empyema was observed. Endoscopic intranasal treatment was applied in 9 patients (21.4%) with fronto-ethmoidal, spheno-ethmoidal and maxillar mucocoele. Complete recovery was observed in 30 (71.4%) patients, recurrence was noted in 12 (28.6%) and these patients were operated from extranasal approach. CONCLUSIONS Paranasal sinuses mucocoele is found when natural ostia of sinuses are blocked after prior operation. They cause destruction of bony walls of sinuses. Extranasal approach is an optimal method of treatment in extended mucocoele and their complications.