This article will examine the level of sustainability for companies in Continuous Improvement Management and the factors which are supporting sustainability during time, through a survey to 350 companies of Basque Autonomous Community and Navarra in June of 2009. The study presents some data about the development of the improvement systems. Then, factors that companies have related to the abandonment of improvement systems are analysed. Since improvement systems are based on workers’ participation, this study characterizes this participation. Finally, the elements which have been used in the improvement systems by the companies are analyzed, and how objectives and indicators are used in their management system. To conclude, the following key issues are emphasized: a higher involvement of workforce in improvement systems, the integration of improvement system in the management system and the establishment of associated indicators to the system.