The paper aims to analyze the logic and power of open source software (OSS), and to show the ways in which Korean government and companies support developing countries in the field of software development. Many developing countries are considering software industry to be a strategic industry due to the fact that software industry seems to be labor-intensive, or rather knowledge-intensive industry. In this regard, developing countries without huge financial investment can achieve certain level of economic development while leveraging software industry. Concerning software development tools, among recent trends OSS has been regarded as a viable alternative software development tool for developing countries. In developing countries, OSS is believed to resolve some difficulties caused by proprietary software such as Microsoft Windows, which is too expensive to buy for users and developers in low-income developing countries. In this sense, OSS has been considered as only solution for software developing because OSS is able to reduce the cost of software development and to enhance the technological capabilities of developing countries. In addition to the benefit of low cost, we have to shed light on the business model of OSS that is not to sell software licence, but to provide technical support and services. In order to use OSS as much as they can, developing countries have to invest for educating human resources who can develop and implement software system using OSS. These OSS-related policies can lead developing countries to developed countries.