This study aimed to evaluate the effects of the ISO 9000 QMS on automotive authorized sales and service organizations. The effects of ISO 9000 QMS applications on the training activities and employee relations are evaluated through determined items separately for the both types of organizations having ISO 9000 certificate. Then, the states of customer relations are compared in the organizations with and without certificate. With this aim, the total number of the organizations achieved is 105, of which 67 are with the ISO 9000 QMS certificate. According to the findings, there are significant differences in respect of statistical between the level of training/quality activities and the state of employee relations. The same results are found in the customer relations category. However, significant differences have not been achieved in some items, because it is a system which each automotive authorized sales and service firm applies depending on the main company. As a result, it has been obtained that training/quality activities are more regular and the satisfaction level of employees are higher in ISO-9000 certified firms. It can be sated that this situation has a positive impact on customer relations which is the one of the most important objectives of firms.