The number of North Koreans defecting to South Korea is increasing rapidly. They are important people to South Korean society not only for humanitarian reasons, but also for their impact on the future Korean unification and the integration of the two different South and North Korean peoples. However, the defectors have experienced many difficulties in their adaptation to South Korean society due to their own characteristics and due to the misunderstandings of the South Korean people. To obtain comprehensive qualitative data about the characteristics and difficulties of North Korean defectors' adaptation to South Korean society, 58 semi-structured in-depth interviews were performed with 32 defectors who had entered South Korea from 1990 to 1997. Four categories of adaptation difficulties were encountered, which are related with the defectors' suspiciousness, different ways of thinking, searching for new sets of values, and with the prejudice of the South Korean people. Finally, three areas of suggestions for the more successful adaptation of the defectors to South Korean society were made; a need for more comprehensive perspectives on the defectors' adaptation, suggestions regarding educational programs and suggestions for educating the South Korean people.