Background: Hearing loss is a major concern in the patient with head and neck cancer (HNC) undergoing radiotherapy (RT) and/or chemotherapy (CHT). The present study aimed to assess the incidence of sensorineural hearing loss (SNHL) at 6 months follow-up after RT and/or concurrent Cisplatin-based CHT.  Materials and Methods: In this prospective study, 60 patients with histopathologically proven HNC underwent three-dimensional conformal radiotherapy (3DCRT) (35 patients) and concurrent Cisplatin-based CHT and RT (25 patients). The status of the hearing was assessed pre-treatment (baseline), one day, 1, 3 and 6 months after treatment by pure tone audiometry (PTA) and other audiometric tests such as tympanometry (TM), acoustic reflex (AR), and speech audiometry (SA). Results: In the RT group, SNHL was observed in 18 patients and hearing loss occurred in 47 % (33 of 70 ears) of ears. In the chemo-radiotherapy (CRT) group, SNHL was discerned in 20 patients and hearing loss appeared in 88 % (44 of 50 ears) of ears. Perforation of the tympanic membrane occurred in 2/35 patients in the RT group and 1/25 patients in the CRT group. The AR threshold (ART) of patients with CRT significantly increased compared to the RT group at the end of 6 months after treatment (P <0.05). Meanwhile, there was a significant difference in the speech discrimination score (SDS) and speech recognition threshold (SRT) between the CRT group and RT group at the 6 months after treatment (P <0.05). Conclusion: The incidence of hearing loss in patients that underwent CRT was higher. The auditory system should be considered as a critical organ at risk (OAR) in treatment planning.