The third party audit of the systems of quality management may be performed by quality auditors, who represent a certain certifying body, fulfilling the rules of good practice provided therein. Being the interface between the certifying body and audited clients / organisations in different fields of activity, the auditors are selected and trained permanently with a view to improve their performance and implicitly the image of certifying body. The objectives of the article are to present the rules applied within international certifying bodies, from the perspective of that involved directly for almost ten years in this activity, simultaneously with university activity. With respect to the manner of collecting the information, the article relies on the experience of the author in the capacity of third party auditor, competent in the following fields: education, research, trade, tourism, services. The practical issues emphasized in the article refer to the rules appropriated by third party auditors within famous international certifying bodies TÜV Rheinland and respectively TÜV Austria, where the author of the article began and respectively carries out his activity currently. Their image and fame is due to the rules of good practice, fulfilled in these certifying bodies for over 130 years. The article presents the stages of theoretical and practical formation of an auditor, the objectives to be reached on each stage of preparation, what his activity involves within the certifying body, the collaboration with the other auditors, permanent training and experience exchanges during the international conferences organised by certifying bodies, practice of audit, possibility of maintaining as auditor and advancing as chief auditor, the status of third party auditor.