AIM An obstructive condition of paranasal sinus secondary to surgery, trauma, flogosis or neoplasms could become a predisposing state to the occurrence of mucocele. Frontal sinus mucoceles, which can turn into mucopyoceles due to bacterial super-infections, may invade the orbit, erode the skull base and displace respectively the ocular bulb and the frontal lobe. The surgical treatment of this disease ranges from mini-invasive approaches, such as the transnasal endoscopic marsupialization, to a more aggressive surgery such as osteoplasty through coronal flap and frontal sinus exclusion by fat tissue. METHODS From 2005 to 2007, we treated with transnasal endoscopic surgery 10 patients, affected by frontal sinus mucopyoceles displacing both the ocular bulb and the frontal lobe. RESULTS AND DISCUSSION In the present study, we report the clinical and diagnostic features of this series, the treatment modalities and the achieved results and confirm the effectiveness of the mini-invasive transnasal endoscopic technique in the treatment of the frontal sinus mucopyocele.