Assessment and management of older people with cognitive impairment, especially those associated with psychiatric symptoms; are recognised as core capabilities of old age psychiatrists. Bi-national collections of HoNOS65+/HoNOS reveal that over 40% of older people entering public mental health services across Australia and New Zealand have a clinically significant rating on the HoNOS65+/HoNOS cognitive problem scale, with rates increasing with age, and significant regional variability. The high rates of cognitive impairment in these data reinforce the need for all mental health clinicians working with older people to have the capability to assess people with cognitive impairment. Once cognitive impairment is identified, clinicians must be equipped to incorporate the implications into individualised management plans, appropriate referral pathways and community support services. Such skills cannot be the sole responsibility of old age psychiatrists or aged care psychiatry services given the significant number of older people seen by adult mental health services. Regional variability in rates of cognitive impairment raises significant questions regarding variation in service eligibility criteria, equity of access to appropriate mental health care and the availability of a workforce and clinical environments that can meet the needs of older people with cognitive impairment. Finally, psychiatry trainees must learn about working with older people with various degrees of cognitive impairment as part of providing high-quality psychiatric care for an ageing population.