Dementia and delirium are two common neuropsychiatric conditions affecting older adults. Although both involve disturbances in cognitive functioning, they differ significantly in their causes, onset, progression, symptoms, management, and prognosis. Proper understanding and early identification are essential because timely intervention can improve the quality of life of elderly individuals and reduce complications. Dementia is a chronic, progressive syndrome characterized by a decline in cognitive functions severe enough to interfere with daily life and independent functioning. It results from damage to brain cells caused by conditions such as Alzheimer's disease, vascular dementia, Lewy body dementia, and frontotemporal dementia. Alzheimer's disease is the most common cause of dementia in old age. Risk factors include advancing age, family history, hypertension, diabetes, smoking, obesity, stroke, and low educational attainment. The major symptoms of dementia include gradual memory loss, particularly of recent events, difficulty in learning new information, impaired judgment, language problems, confusion regarding time and place, inability to perform familiar tasks, personality changes, mood disturbances, and loss of social skills. As the disease progresses, patients become dependent on caregivers for personal care, feeding, and mobility. Behavioral and psychological symptoms such as agitation, aggression, wandering, hallucinations, depression, anxiety, and sleep disturbances are also common. Diagnosis of dementia involves detailed history taking, cognitive assessment, neurological examination, laboratory investigations, and brain imaging when required. There is no complete cure for most forms of dementia, but treatment aims to slow