This study devises a methodology to measure the economic significance of national park tourism, which is applied to the State of Queensland, Australia. Development of a methodology to provide this information is important to demonstrate the attraction of national parks to tourism and to provide a basis for government decisions on allocating funds for national park management. A strategic national park sampling logic was developed to allow surveys to be conducted in a stratified, representative sample of the over 500 Queensland parks. Data on expenditure by tourists were analyzed (employing sensitivity and risk analysis) to find the "national park-generated" component of tourist expenditure directly attributable to the attractions of the national parks. A deliberately conservative approach was taken to address the economic information needs of State Treasury Departments, which are responsible for allocating funding to park management authorities. The contribution to the gross state product (GSP) was estimated at $345 million annually, representing 4.9% of tourism's contribution to GSP, or five times the current annual government expenditure on national park visitor management in the State of Queensland. Recommendations for some improvements to the methodology were developed based on the study conducted.