Background: Adult-onset otitis media with effusion (AO-OME) is relatively difficult to characterize, because of its associated co-morbidities. Objectives: To quantify the burden, assess co-existing diseases, and management of patients with AO-OME. Design of the Study: A descriptive observational prospective study. Setting: Clinical department in a tertiary hospital. Materials and Methods: Adult patients with conductive hearing impairment without ear discharge (excluding other pathologies) nor external ear pathology were eligible. The patients also had tympanometry with type B tracings (tympanograms). Interventions: Clinico-demographic characteristics, history of otologic symptoms, affected ear, and hearing impairment were obtained. Pure-tone audiometry (PTA), tympanometry, and radiological investigations were performed. Other existing diseases (co-morbidities) were noted. The main outcome measure was audiologically confirmed AO-OME. Results: Prevalence of AO-OME was (110/3452) 3.2%. Young adults (age group 18–30 years) constituted 33.7% (28/83), mean age was 37.3 ± 11.5 years, and 46/83 (55.4%) were males and 37/83 (44.6%) were females. The common otologic symptoms were feeling of fullness in the ear in 27.7% (23/83), hearing loss in 24.1% (20/83), and bilateral ear involvement in 32.5% (27/83). PTA revealed 8.2% (9/110) had normal hearing, whereas 62.7% (69/110) ears had conductive hearing loss. Patients had radiological investigations, namely plain X rays in 67.5% (56/83) and computerized tomography scan of sinuses in 10.8% (9/83). Three (3/83) patients (3.6%) each had nasoendoscopy, and nasal and nasopharyngeal examination under anaesthesia and biopsy. The major associated diseases (co-morbidities) were allergy in 38.6% (32/83), infective rhinosinusitis in 24.1% (20/83), and upper respiratory tract infection in 14.5% (12/83). Conclusion: Prevalence of AO-OME was 3.2%. AO-OME co-existed commonly with allergy and other inflammatory diseases of the upper respiratory tract. The management was conservative medical management.