Objectives: Describe clinical manifestations of atelectasis by examined endoscopy. Subjects and Methods: Clinical oservations were made on 122 ears from 90 who had examined by ENT endoscopy for the diagnosis of atelectasis at the Thai nguyen university of medicine Hospital from 1/2014 to 10/2014. Results and Conclutions: That condition where the tympanic membrane is displaced toward the promomtory is termed atelectasis. Ninety patients (122 ears) showing various degrees of atelectasis graded from stage 1 to stage 4 were studied. The average age of study group 32,7. Ages are usually disease from 16 to 45 years old accounted for 62,5 percent, the lowest was 8 years old and the highest age was 67 years old. The proportion of women atelectasis are more than the corresponding tate for men was 56,7 percent and 43,3 percent. On a patient with an atelectasis Frequently one ear 58/90 (64.4 percent) have more than 2 ears atelectasis 32/90 (35,6 percent). Functional symptoms are the most common hearing loss and tinnitus proportionately is 87,8 percent and 79,7 percent. Earache least common (16,3 percent). 11,2 percent of patients have no symptoms functional ear. Physical symptoms: Rating total atelectasis 74,2 percent had more than 25,8 percent of focal atelectasis. Patients often examined in the late stage 3 and stage 4 about 92/122 ears accounted for 75,4 percent occupancy rate. The positive experience in legal valsava are 100 percent at stage 1 and stage 2 and 90.2 percent at stage 3. But the negative experience in legal valsava are 100 percent at stage 4 and 9,8 percent in stage 3.