PURPOSE: The purpose of this study was to identify type of anger expression and mental health in middle aged women. METHODS: From August to October 2005, survey data were collected by using the State Trait Anger Expression Inventory and Symptom Check List-90-Revision (SCL). Participants (1,442) were classified into four types of anger expression by K-mean cluster analysis. For collecting interview data for content analysis, 18 participants (4-5 participants from each type of anger expression) were recruited. The interview data were collected between March and September 2006. RESULTS: The average score of the state anger of middle-aged women was 11.95, and that of the trait anger was 18.75. The average anger expression scores were 12.72 for Anger-In, 13.45 for Anger-Out, and 18.51 for Anger-Control. The average SCL scores were 45.03 for somatization, 42.23 for obsessive-compulsiveness, 42.44 for interpersonal sensitivity, 42.45 for depression, 42.40 for anxiety, 42.62 for hostility, 44.44 for phobic anxiety, 43.65 for paranoid ideation, and 43.08 for psychoticism. The anger expression types identified in this study were 1) anger-out in secret, 2) anger-control with a patience, 3) anger-out with suppression, and 4) low anger expression type. The psychosomatic symptom scores were the highest in type III (anger-out with suppression), and the lowest in type IV (low anger expression type). CONCLUSION: This study can be helpful in assisting middle aged women to control their anger effectively and may contribute to the improvement of their mental health.