The experience of music is difficult to study objectively. Here we describe a detailed analysis of musical hallucinations developing after a probable brainstem stroke in an 83 year old musician who was able to describe and notate the hallucinations. The hallucinations comprised simple, repetitive melodic and rhythmic motifs that were combined apparently randomly without definite tonality, large-scale structure, or timbre. This observation is consistent with the proposal that musical hallucinations represent abnormal spontaneous activity in auditory cortical areas beyond the primary auditory cortex. This activity may generate novel musical motifs.