This paper explores the impacts of information technology investment on economic growth in a cross-section of 39 countries in the period 1980-95 by applying an explicit model of economic growth, the augmented version of the neoclassical (Solow) growth model. The results based on the full sample of 39 countries indicate that physical capital is a key factor in economic growth in both developed and developing countries. Its influence is even bigger than what is implied by the income share of capital in national income accounts. But neither human capital nor information technology seems to have a significant impact on GDP growth. However, investment in information technology has a strong influence on economic growth in the smaller sample of 23 developed (0ECD) countries. Its impact is almost as large as that of the rest of the capital stock. But since the share of IT investment in GDP, although growing, is still much lower than the share of non-IT investment, the net social return to IT capital is much larger than the return to non-IT capital: 60-80 per cent versus 4 per cent, respectively. The estimated return is very high; about twice the return to equipment investment and 10-12 times the return to R&D obtained in similar models as the one applied here.