The Delirium Rating Scale is a clinician-rated, 10-item symptom rating scale for assessment of delirium severity. In order to better understand the relationship between items of the scale and whether they reflect one or more underlying groupings or dimensions, further analyses of the originally published scale data were performed. Factor analysis revealed a strong single underlying dimension that could be further divided into two components: one comprising delusions, psychomotor behavior, cognition, sleep-wake cycle disturbance, and mood lability; the other comprising temporal onset of symptoms, perceptual disturbances, hallucinations, and fluctuation of symptoms. Implications for improved phenomenological understanding of delirium are discussed.