This paper tries to find the factors to influence the happiness of Korean Adventists. The data of 1,061 respondents from 25 churches in the South-East Korean Conference were used in this study. The dependent variable, happiness, was assessed through nine different questions and independent variables consist of three categories: satisfactions with family, satisfactions with finance, and religiosity. The section of religiosity is divided into different four groups of questions: satisfactions with attending church, practice of Adventist beliefs, conviction of Adventist beliefs, and pride of the Adventist church. Even though satisfaction with family and satisfaction with finance and all the religiosity measures are positively and significantly related to the index of happiness of the Adventists in Korea, the satisfaction with family is the most influential factor for the happiness. The financial satisfaction is the second influence and the religiosity is the least influential. Finding shows that among religiosity measures the most influential factor is the pride of the Adventist church, but the conviction of the Adventist beliefs is negatively related to the happiness of the church members.