Objective:To investigate the relationship between submandihular gland droop and Obstructive Sleep Apnea Syndrome (OSAS).Methods:20 patients with established OSAS were randomly checked up through CT scanning and MR examining. PolySomnoGraphy(PSG)was performed before operation

and submandibular morphology was studied

symptoms sumed up

8 vol- unteering patients underwent PSG after operation.patients and their familymembers were investigated in the follow-up.Results: 20 patients with OSAS developed submandibular gland droop

including downwand displacement and swelling.AHI was monitored to be below 14.90 in 8 cases pastoperatively;OSA disappeared in 12 patients and notable relief of OSA Occurred in 8 patients; snoring was eliminated in 8 patients

lowered in 12 patients;daytime fatigue disappeared in all patients

and diastolic pressure decreased to lower than 90mmHg in hypertensive patients.No recurrence was found in the 12-24 months of follow up.Conclu- sions:submandibular gland droop is a complication of snoring

submandibular gland droop and swelling let the base of tongue fall back

and the body of tongue run up.Submandibular gland droop is the most significant cause for OSAS.Removal of droop- ing submandibular gland is an effective cure for OSAS.