Purpose: In this study the level and type of friendship in a hospital was identified, and the influence of the level and type of friendship on the organizational performance was investigated, and then the role and direction of a hospital that can improve the organizational performance was searched. Methods: A structured survey tool suitable to achieve the study purpose was utilized, and surveys were made on the nurses, administrators and medical technicians that work at 24 tertiary hospitals in Seoul and Kyongin area, and the recovered 401 questionnaires were analysed by the metho ds such as frequency analysis, T-test, One-way ANOVA, Chi-square test, two-way ANOVA and hierarchical regression analysis. Results: As for the influences of friendship level and type on organiza tional performance as follows: in case of job satisfaction, the higher the friendship level with superiors and subordinates, the higher t he job satisfaction and the type of heart is higher in job satisfaction than that of brain; in case of organizational commitment, the higher the friendship level with superiors, subordinates and fellows, the higher the organizational commitment but, there is no statistically significant difference in the friendship type; in case of job stress, the higher the friendship level with superiors and fellows, the lower job stress and the type of hea rt is lower in job stress than that of brain. Conclusion: Integrating above study result the friendship in an organization is thought to influence very much on the factors of achievement of an organization such as job satisfaction, organizational commitment and job stress.