In our country there have been many efforts in recent years to introduce laws that lead to the introduction of the concept of quality in the field of public hospitals. The implementation of health quality systems contributes to health care improvement, while the assessment of quality services is a basic tool in quality management. Purpose: The purpose of the study was to describe the benefits that can be gained by a public institute of health when a quality model is applied. Material and methods: This paper focus on the application of the ISO 9001:2008 standard in the Intensive Care Unit of the General Hospital of Larissa during the years 2010-2012. The results and benefits of its implementation, recorded by measuring satisfaction of the relatives of the patients. The questionnaire Family Satisfaction with Care in the Intensive Care Unit (FS-ICU 24) and quality indicators were applied. The study sample was all the relatives of the patients hospitalized in ICU during 2010-2012. Descriptive statistics was performed. Results: Quality indicators were considerably improved after ISO implementation with SMR falling to 35% in 2012 (from 58% in 2007), thus being one of the lowest in Greece and below European ICU’s SMR mean value. Over 80% of patients’ relatives answered that Nursing and Medical care was “excellent” and over 10% characterized it as “very good”. Family members’ total satisfaction surpassed 90%. Medical and Nursing care were highly appreciated by family members (very positive attitude expressed by over 90% of participants) and satisfaction from nursing services approaches 100%. Conclusion: The implementation of quality systems in healthcare organizations is not easy and has many dimensions. However, it offers competitive advantage, improves the efficiency and effectiveness of the health care service providers and substantially contributes to the improvement of the delivered heath care.