Musical hallucinosis is a rare and poorly understood clinical phenomenon. While an association appears to exist between this phenomenon and organic brain pathology, aging and sensory impairment the precise association remains unclear. The authors present two cases of musical hallucinosis, both in elderly patients with mild-moderate cognitive impairment and mild-moderate hearing loss, who subsequently developed auditory hallucinations and in one case command hallucinations. The literature in reference to musical hallucinosis will be reviewed and a theory relating to the development of musical hallucinations will be proposed.