The family is a system which maintains homeostasis through the relationship between family members and interaction with environment. So, the family is of crucial importance to the menta health of the family members who make up the family system. In the adolescent developmental stage, adolescents are very vulnerable mentally because they are irritable emotionally. There are many studies that have reported mental disorders in adolescence as being related to family factors such as difficulties in family interaction and relationship between family members. Most studies about adolescents with mental disorders have dealt with the relationship between varied factors within the family. This descriptive study was done to provide the basic data on adolescents with mental disorders by testing Olson`s Circomplex Model which is based on family systems theory. Fifty four adolescents with mental disorders admitted to or attending three hospitals in Seoul for psychiatric care made up the sample for this study. The comparative group was made up of 124 high school and college students with no reported history of psychiatric care. Data collection was carried out by the researcher from March 21 to May 10, 1992. The data were analyzed by SPSS program and the hypotheses were tested using mean score, SD, t-test, x2-test, ANOVA and ANCOVA. The results of this study are as follows : 1. The mean score for the normal adolescents was 34.36, and the mean score for the adolescents with mental disorders was. 31.90. The first hypotheses that there is a difference between the two groups as to the mean score of family cohesion was supported (F=5.2573, p＜.05). 2. The mean score for the normal adolescents was 20.10, and the mean score for the adolescents with mental disorders was 27.33. The second hypotheses that there is a difference between the two groups as to the mean score of family adaptability was supported(F=8.7236, p＜.05). 3. In normal adolescents, `Balanced types` was found in 25.0% of the sample, `Mid-range types` in 58.9%, and `Extreme types` in 16.1%. In adolescents with mental disorders, `Balanced types` was found in 35.2% of the sample, `Mid-range types` in 59.3%, and `Extreme types` in 5.3%. The third hypotheses that there is a difference between the two groups as to family types was not supported(x2=4.6450, p＜.05). 4. Adolescent`s age and education level, mother`s age, mental disorders in parents and whether the parents were the real parents or not were related to the mean score of family cohesion. Father`s education level, mental disorders in parents and whether the parents were the real parents or not were related to the mean score of family adaptability. No statistically significant relation was found between any of the adolescent`s characteristics and family types. 5. In the test of difference in the mean score of family cohesion and adaptability between the two groups when the four variables-father`s age and job, mental disorders in parents, whether the real parents or not which showed a difference between two groups were controlled, it was found for the varibles father`s age and job, there was a difference between the sores for two groups on family cohesion and adaptability. But, for the variables mental disorders in parents and whether the real parents or not, it was found that there was no difference the scores for between two groups on family cohesion and adaptability. This study suggests that there is a need for more studies with matched samples including age and education level of adolescent, age of mother, education level of father, parents with mental disorders and addressing the question of whether parents are the real parents or not as well as more studies with samples including other family members in addition to the adolescents.