The effects of diabetes mellitus include long-term damage, dysfunction and failure of various organs. Aims and objectives: The objectives of this study were to determine the prevalence of hearing loss in primary (Types1 and 2) diabetes mellitus seen in the University of Nigeria Teaching Hospital (UNTH), Enugu, the type of hearing loss, the correlation (if any) between the severity of hearing loss and duration of diabetes and comparism between the hearing thresholds of Type 1 and Type 2 diabetes mellitus patients. Methodology: This was a prospective hospital-based study conducted from April 2005 to March 2006 on adults suffering from diabetes mellitus of 5 years or more duration; and sex and age matched non-diabetic volunteers, in UNTH, Enugu. Results: The age range was 26-80yrs and 25-79yrs with a mean of 47.56 and 44.56 for diabetic and control groups respectively. The 2 sex ratio M:F was 1:1 for both diabetics and control. The prevalence of hearing loss was 46.9% made up of 43.8% sensorineural hearing loss and 3.1% conductive hearing losses. 21.9% had moderate to severe hearing impairment. The longer the duration of diabetes mellitus the worse the hearing impairment. Hearing was better in Type 1 compared to Type2 diabetes mellitus patients. Conclusion: It was concluded that the prevalence of SNHL in diabetics is high and slowly progressive. Recommendations: It was, recommended that diabetic patients should have regular hearing assessment at least 6 monthly for early detection of hearing loss. Key Words: Hearing loss, Diabetes Mellitus, Pure tone audiogram