This investigation focused on problems of foreign laborers, particularly illegal Karen immigrants from Burma working in Mae Sot District, Tak Province. The issues under investigation included problems of illegal laborers replacing Thai laborers in basic occupations, a comparison of the quality of foreign and Thai laborers, impacts of illegal laborers on national security, the district's losses through the export of remittances, the negative image of the country in the eyes of foreigners, and prostitution by Karen workers. The data were collected by surveying and interviewing business people, government officials, tambon chiefs, village headmen, and local politicians. The investigation also examined the livelihood of the Karen laborers, their living conditions, how they entered into Thailand, their jobs, and job aspects. The sample group was illegal Karen workers of Burmese nationality residing and working in the district.
    
          It is found from the study that there were a large number of illegal Karen workers in the district. The reasons for their illegal entry were escaping from wars before looking for jobs and escaping from poverty due to economic problems in Burma. Most of these illegal workers came from the capital city of the Karen State. These illegal workers were mostly young men and women working as laborers, handymen, factory workers, restaurant workers, and domestic workers.