This paper uses newly available estimates of the capital stock to explore the role of capital in the economic performance of the various states of Australia, in terms of gross state product per capita and labour productivity. A variant of standard growth decomposition methodology is used, allowing distinction to be made between the impact of changes in the output-to-capital ratio and that of capital deepening (an increase in the capital-to-labour ratio). Both of these factors are found to have played important roles in determining output and labour productivity growth. Analysis is also made of estimates of the capital stock disaggregated by type. The results suggest that interstate variations in the private-sector components of the capital stock, particularly those categorised as 'machinery and equipment' and 'non dwelling construction', have been more influential on relative performances with respect to aggregate output growth than those associated with the public-sector components.