Objective: to analyze the own results of endoscopic transethmoidal orbital decompression (ETOD) in endocrine ophthalmopathy (EOP). The paper analyzes the complications occurring in the early and late periods after nasal cavity and paranasal sinus surgery. It provides quantitative and qualitative assessments of the found complications and gives the results of their treatment. Subjects and methods. 50 patients with EOP in the stage of medical compensation or complete remission of the main process have been operated on at the Ear, Nose, and Throat Clinic, I.M. Sechenov First Moscow State Medical University, in 2006 to 2016. ETOD has been performed in 22 and 28 patients with unilateral and bilateral exophthalmos. A total of 78 orbits have been operated on. Results. The main postoperative complaints were impaired nasal breathing (34%), dry nose and increased crusting (44%), discharges from the nose and along the posterior pharyngeal wall (16%), nosebleed (2%), pains in the forehead (2%) and upper jaw (8%), and headache (2). Post-ETOD endoscopic study revealed nasal synechiae at different sites (48%) and discharges from the maxillary (16%) and frontal (2%) sinuses. Eight (16%) patients were diagnosed with maxillary sinusitis; 1 (2%) patient had acute frontal sinusitis and 1 (2%) had sphenoid sinus mucocele. The complications were eliminated by medical treatment and additional surgical interventions. Analysis of the findings indicated that the complications were due to inadequate postoperative care of the nasal cavity, to the extremely large size of the bone hole formed at ETOD, and to the resection of the inferior orbital wall. The magnitude of the possible postoperative impact of orbital soft tissues on the physiological indicators of the function of the paranasal sinuses, among other processes, on the block of their drainage pathways by the prolapsed orbital tissues was estimated. Several possible variants to reduce the risk of postoperative complications were proposed. Emphasis was laid on the necessity of improving the surgical treatment of EOP.