As the growth of international marriages increased, this thematic analysis study focused on mothers-in-law in multicultural families in South Korea. This study explored mothers-in-law‟s experiences of living with an immigrant daughter-in-law in multicultural families in South Korea. This study used thematic analysis of qualitative methods, included 10 mothers-in-law selected from rural areas. The participants‟ attitudes toward the marriage of their son were divided into three stages; “the early stage,” “acceptance of the international marriage,” and “life at present.” These three stages comprised 5 themes and 14 sub-items. Mothers-in-law living with an immigrant daughter-in-law had many physical illnesses, psychological problems, and they felt guilty or that they had sinned. However, they had no support system. Participants of this study wanted to receive social support and sincere human relationship. In practice, the Korean society needs to change its perception and develop positive attitudes toward multicultural marriages.