In this study, we evaluated the diagnosis and factors underlying the development of intractable dizziness/vertigo in patients managed at a university hospital by retrospective analysis of patients’ medical records. The participants included 78 patients, comprising 35 men and 43 women, who visited our outpatient department on account of intractable dizziness between April 2021 and December 2022. The associations between the duration of illness and 10 different variables were evaluated. The median age was 65.5 years, and the median duration of illness was 305.5 days. Among the patients, 60% were referred from otorhinolaryngology departments. Other peripheral vertigo conditions associated with vestibular dysfunction formed the most commonly diagnosed conditions, followed by benign paroxysmal positional vertigo, dizziness of unknown cause, Meniere’s disease, vertigo-associated primary headache, persistent postural perceptual dizziness, central vertigo, and orthostatic dizziness. Among the other peripheral vertigo conditions associated with vestibular dysfunction, compensatory vestibular insufficiency was suggested to be present in 12 patients. Ten of these patients were aged. In most cases of unknown cause, lack of characteristic findings or additional investigations underlie the lack of a known cause. Multivariate analysis revealed that age and comorbidity of multiple dizziness disorders are factors associated with the duration of illness. In diagnosing refractory vertigo, loss of characteristic findings, prolonged vestibular decompensation, necessity of examination in other departments, comorbidity of multiple dizziness disorders, and repetitive nature of the disease should be considered. In older patients with multiple episodes of dizziness, diagnosis and treatment should be made with consideration for the prolonged duration of illness.