A market survey of the European MBR industry was performed, contacting 33 Suppliers or retailers of MBR filtration systems and/or MBR plant constructors. We identified MBR plants constructed up to 2005, and about 300 references of industrial applications (> 20 m(3)/d) and about 100 municipal wastewater treatment plants (WWTPs > 500 p.e.) were listed. On average, the capacity of industrial applications is an order of magnitude smaller than municipal applications (median flows of 180 m(3)/d and 2,500 m(3)/d respectively). In the coming years, at least 70 new MBR plants are expected to be constructed annually, with about 50 industrial and 20 municipal applications. Taking the installed membrane surface as indicator of market share, it appears for the period 2003-2005 that the municipal sector represented 75% of the market volume. The predominance of immersed MBR filtration systems in both sectors is undisputed, as during this 3-year period they represented 99% of the total installed membrane surface (Zenon-GE and Kubota, 2 non-European suppliers, representing 63% and 30% respectively). If the industrial market can be considered as mature and stabilized, the municipal market is expected to witness further growth over the next decade under the combined effects of the acceleration of plant construction and the capacity increase. This provides a commercial opportunity for novel European-manufactured technologies to increase their share in the European and global MBR markets.