The ISO 9000 quality systems have proved to be a useful management tool. Nevertheless, the demands of the society have extended to additional areas of management systems. In this context, integrated management systems have been increasingly implemented in companies that want to ensure compliance of several standards, thus reducing the working documentation, the evaluation time and the costs of developing and maintaining such a system. The purpose of this research is to assess the level of implementation of integrated management systems in Croatian foreign export companies operating in the industrial and agricultural sectors, ie to determine the percentage of Croatian foreign export companies certified to ISO 9001, ISO 14001, OHSAS 18001 and other standards, as well as to determine whether they can lead to the increase of Croatian exports and, if so, to what extent. The joint implementation of the ISO 9001 and ISO 14001 standards together with other standards analysed in this paper provides the basis for sustainable development and hence for the overall quality of management.