Background: Specialist health services are often organised on a regionalised basis whereby clinical resources and expertise are concentrated in areas of high population. Through a high volume caseload, regionalised facilities may provide improved clinical outcomes for patients. In some cases, regionalisation may be the only economically viable way to organise specialist care. While regionalisation may have benefits, it may also disadvantage some population groups, particularly in circumstances where distance and time are impediments to access. Queensland is a large Australian state with a distributed population. Providing equitable access to specialist healthcare services to the population is challenging. Specialist care for critically ill or injured children is provided by the Queensland Paediatric Intensive Care Service which comprises two tertiary paediatric intensive care units. The two units are located 6 km (3.7 miles) apart by road in the state capital of Brisbane and provide state-wide telephone advice and specialist retrieval services. Services also extend into the northern area of the adjacent state of New South Wales. In some cases children may be managed locally in adult intensive care units in regional hospitals. The aim of this study is to describe the effect of geography and service organisation for children who need intensive care services but who present outside of metropolitan centres in Queensland. Methods/design: Using health services and population data, the availability and spatial accessibility to paediatric intensive care services will be analysed. Retrieval utilisation and the associated costs to the health service will be analysed to provide an indication of service utilisation by non-metropolitan patients. Discussion: While the regionalisation or centralisation of specialist services is recognised as an economical way to provide specialist health services, the extent to which these models serve critically ill children who live some distance from tertiary care has not been described. This study will provide new information on the effect of the regionalisation of specialist healthcare for critically ill children in Queensland and will have relevance to other regionalised health services. This study, which is focussed on describing the organisation, supply and demands on the health service, will provide the foundation for future work to explore clinical outcomes for non-metropolitan children who require intensive care.