Pulsatile tinnitus (PT) is the auditory perception of rhythmic noise in time with the heartbeat. It attracts the interest of neurological, ENT and vascular specialities, each approaching symptom investigation with a different emphasis, and the risk of overlooking other PT aetiologies. The diverse range of aetiologies presents a challenge for the otolaryngologist, made more challenging by the critical need to exclude life-threatening vascular causes. This study proposes a diagnostic algorithm for PT. It describes the key symptoms and signs as well as their combined value in guiding the most appropriate investigations. Methods: A prospective cohort study was performed on consecutive patients referred to a single United Kingdom tertiary centre between 2010 and 2023 for investigation of primary intractable PT. Results: 778 patients were referred over the study period.. Females represented 72.9% of the cohort. Middle or inner ear pathology accounted for only 50 cases (6.4%). Thirty patients (3.9%) were found to have a dural arteriovenous fistula. Application of the algorithm arrived at a diagnosis of venous PT (VPT) in 38.0% of patients, arterial PT in 1.4%, arteriovenous 4.2%, cardiac 0.3%, temporal bone pathology 6.4%, and somatosensory (SSPT) in 30.9%. Compression of the ipsilateral internal jugular vein resulting in reduced PT was the strongest clinical sign in VPT, present in 82.3%. Sigmoid sinus wall defects were observed only in the VPT group (48.7%). Females were more likely to have evidence of raised ICP and an eventual diagnosis of intracranial hypertension (22.1% vs 4.3%). Discussion This study identifies PT traits and radiological findings that help differentiate underlying pathologies, bringing together all PT causes under one classification system. Additionally, it highlights the difficulty that is occasionally faced when trying to differentiate VPT from SSPT. The incidence of objective PT and its underlying aetiologies raises the importance of early diagnosis.