This aper documents the available evidence on international portfolio investment in five OECD countries. We draw three conclusions from the data. First, there is strong evidence of a home bias in national investment portfolios despite the potential gains from international diversification. Second, to the extent investors hold international securites, the composition of the portfolio of foreign securities seems to reflect factors other than diversification of risk. Third, the high volume of cross-border capital flows and the high turnover rate on frieign equity investments relative to domestic equity markets suggests that trnsactions costs and incomplete information are unlikely to be important deterrents to international investment. These observations suggest that a richer set of models is required to account for international investment behavior.