Objective: To estimate service demand (willingness to seek or use services) for respite care among informal, primary carers of people with a psychological disability and to describe their characteristics. Methods: Analysis of data from the household component of the 2009 Survey of Disability Ageing and Carers (n=64,213 persons). Results: In Australia in 2009, 1.0% of people aged 15 years or over (177,900 persons) provided informal, primary care to a co-resident with a psychological disability. One-quarter (27.2%) of these carers reported service demand for respite care, of whom one-third had used respite services in the past three months and four-fifths had an unmet need for any or more respite care. A significantly greater percentages of carers with service demand for respite care spent 40 or more hours per week on caregiving, provided care to a person with profound activity restrictions and reported unmet support needs, compared to carers without service demand. Lack of suitable, available respite care models was a barrier to utilisation. Conclusions: Findings confirm significant service demand for, and under-utilisation of, respite care among mental health carers. Implications: Increased coverage of respite services, more flexible service delivery models matched to carers’ needs and better integration with other support services are indicated.