Background
: The family type of our country is mixed with extended family and nuclear family, it is different from western but has not been compared and studied objectively. Then we performed this study to compare and analyze the family function of two family types for helping the family medicine treatment.

Methods : We have selected 65 extended family and 65 nuclear family in the Seoul and Gyounggi-Do and evaluated their family function by Olson's FACES III.

Results : In FACES III cohesion of extended family, there were 5 cases(7.7%) in disengaged, 23 cases(35.4%) in separated, 29 cases(44.6%) in connected and 8 cases(12.35%) in enmeshed. In that of nuclear family 20 cases(30.8%) in disengaged, 26 cases(40.0%) in separated, 16 cases(24.6%) in connected and 3 cases(4.6%) in enmeshed. In FACES III adaptability of extended family, there were 17 cases(26.2%) in rigid, 21 cases(32.3%) in structured, 18cases(27.7%) in flexible and 9 cases(13.8%) in chaotic. In that of nuclear family 8 cases(12.3%) in rigid, 11 cases(16.9%) in structured, 26 cases(40.0%) in flexible and 20 cases(30.8%) in chaotic. In FACES III family type of extended family there were 31 cases(47.7%) in balanced, 29 cases(44.6%) in midrange and 5 cases(7.7%) in extreme. In that of nuclear family 21 cases(32.2%) in balanced, and 37 cases(56.9%) in midrange and 7 cases(10.8%) in extreme.

Conclusion : Cohesion scale of extended family was higher than that of nuclear family and adaptability scale of nuclear family was higher than that of extended family.