This study purports to investigate the relationship between workplace friendship and organizational effectiveness in general hospitals. Organizational effectiveness was represented by the level of job satisfaction, organizational commitment, stress, and intent to leave. Data were collected from 372 workers at 6 hospitals in Chungbuk Province using self-administered questionnaires from May 1 to 20, 2009, and analysed using t-test, ANOVA, correlation analysis and multiple regression analysis. The major findings of the study are as follows: First, friendship level of hospital employees is highest in the friendship with colleague, followed by the friendship with subordinates and with superiors. Second, the group of higher level of workplace friendship showed significantly higher level of organizational effectiveness than the group of lower level of workplace friendship. Third, the level of the workplace friendship with superiors and colleagues was found to have a significant positive impact on the job satisfaction and organizational commitment. The level of the workplace friendship with superior was found to have a significant negative effect on the intent to leave and work stress. These results imply that hospital managers should make an effort to create the organizational climate and systems which improve the workplace friendship.