There has been limited research on the incentives foreign institutional investors face in foreign markets. We investigate whether foreign institutional investors are long term investors using the Korean stock market data. We measure the influence level of foreign institutions using the trading share of foreign institutions in the total trading volume of a firm as well as ownership of foreign institutions. We find a positive relationship between the influence level of foreign institutional investors and opportunistic earnings management. This result suggests that they have a short investment horizon and seek information-based trades. We also find that the positive relationship between foreign institutional investors and earnings management intensifies during periods of low market growth, and in firms with lower managerial ownership or firms unaffiliated with large conglomerates. These findings suggest that monitoring incentive and investment horizon of foreign institutional investors depend on economic environment, market growth and corporate governance characteristics in emerging markets.