Sleep and circadian disturbances are common among patients with dementia. Symptomatic manifestations vary according to dementia subtype, with one commonly shared pattern--the irregular sleep-wake rhythm (ISWR), a circadian disorder characterized by an absence of the sleepwake cycle’s circadian synchronization. Hypothesized mechanisms of circadian rhythm disturbance include suprachiasmatic nucleus (SCN) circadian pacemaker damage, pineal gland and melatonin secretion alterations, and reduced zeitbeigers and decreased input to the SCN. Management options include prescribed sleep/wake scheduling, light therapy, melatonin, physical and social activity, and mixed modality. The mixed-modality approach is the most effective method in treating ISWR. Pharmacologic interventions are controversial, with no evidence supporting their effectiveness while associated with multiple side effects. They should be used with caution and only be considered as short-term therapy. All treatment strategies should be individualized to achieve the best outcomes.