International diversification decreases systematic risk that can not decrease by domestic diversification. This research is about integration, interdependence and contagion in developed markets, emerging markets and a combination of developed and emerging markets in the Mortgage Crisis. Johansen is being used for how far developed market integrated hat emerging markets are . The Contagion was signed by increasing the correlation but there is a bias in correlation so Fisher is used in this research. The results of this study indicate that developed markets are more integrated than emerging markets. Therefore, investing in emerging markets can have less country than developed markets. Contagion happened in Ireland and Qatar. As a result, investment companies need to invest in interdependence country than in contagion country.