Objectives: To investigate prevalence of Eustachian tube dysfunction among patients with neck malignancies after being treated with radiotherapy.Methods: Study was conducted on 20 patients (40 ears) suffering from neck malignancy and treated with radiotherapy who were admitted at the Otolaryngology-Head and Neck surgery department, Kasr-Al Aini hospital, Cairo University during the period from February 2012 to February 2013. Patients subjected to audiological evaluation through pure-tone audiometry (PTA), immitance audiometry (tympanometry and acoustic reflex) and Eustachian tube function tests which made in Audiology department, Kasr-Al Aini hospital.Results: Our study reported 24 ears(60%) with abnormal tympanometry findings, 10 ears(25%) of which were type B denoting middle ear effusion and 14 ears(35%) had type C tympanogram indicating Eustachian tube dysfunction. 36 ears(90%) with absent acoustic reflex bilaterally, 23 ears(57.5%) with poor Eustachian tube function and 10 ears(25%) with blocked Eustachian tube. 13 ears (32.5%) with conductive hearing loss, 8 ears (20%) with sensory neural hearing loss and 3 ears (7.5%) with mixed hearing loss.Conclusions: Patients with neck tumors treated by radiotherapy (apart from the nasopharynx and parotid) have a high incidence of Eustachian tube dysfunction. In those tumors the inner ear function is usually spared as the field of irradiation is relatively distant from the ear.