The elderly patient is particularly susceptible to negative effects on cognition that can arise from certain medications. This may occur whether or not pre-existing cognitive impairment is present. Medications whose primary target is the central nervous system (e.g., antidepressants, antipsychotics, sedative-hypnotics) or those which are targeted at other primary systems (e.g., cardiovascular drugs, urinary anti-spasmodics) should be considered as contributing factors in the patient with confusion or memory decline. Steps that can be taken to reduce this risk include: coordination of medical care among the patient's clinicians to avoid polypharmacy, judicious selection of appropriate medications, use of the lowest effective drug dose, and substitution of non-pharmacologic therapies whenever possible. This chapter addresses potential complications of medication use in older adults with cognitive decline.