Introduction: Increasing pressure to follow a vision on complete health care organizations, better quality and excellence selection systems has become one of the main concerns for organizations and their managers.. Objective: The aim of this study is to determine the relationship between the level of ISO 9001-2008 quality management system and altering indictors of quality effectiveness in Rasht Hospitals. Methods: This is a descriptive and correlational study which was performed in three ISO-certified hospitals. The degree of ISO implementation measured using the requirements of ISO 9001 standards through questionnaires. Data of quality effectiveness indictors were compared using dependent T-test before and after the implementation when determining the mean and coefficient of variation. Results: There was a significant relationship between some indicators of quality effectiveness such as patient satisfaction, number of inspected complaints and improved procedure within implementations of ISO quality system (p<0.05). On the other hand there was no significant difference between the mean alteration of the average length of patient's hospitalization before and after the placement. Conclusion: Create a systemic visualization of the powerful tool such as ISO quality management system and imperative practical performance system in one organization discriminent addition to correcting systems and improving staff performance, will improve some indicators of hospital.