The Blue Mountains Hearing Study (BMHS) has shown that tinnitus affects one in three older Australians with 16% of cases describing severe annoyance. Among persons describing severe symptoms, 52% have sought professional help. We aim to identify factors associated with the severity of tinnitus in 2,015 persons aged over 54 years. Comprehensive questionnaires about hearing were administered. Air- (250-8000 Hz) and bone-conduction (500-4000 Hz) audiometric thresholds of both ears, together with transient evoked and spontaneous otoacoustic emissions, were measured. Factors predicting severity of tinnitus were assessed in Cox proportional hazard models. After multivariate adjustment, factors significantly associated with severe tinnitus were hearing loss (relative risk [RR] 2.9), dizziness (RR 2.0), head injury (RR 2.0), sinus and middle ear infections (RR 1.9), and mastoiditis (RR 3.9). Associations with mild tinnitus included age (RR 0.8), hearing loss (RR 1.4) and history of dizziness (RR 1.5), meningitis (RR 2.2), and migraine (RR 1.5). Knowledge of these factors could contribute to improved tinnitus management.