Summary The aim of this study was to develop a selective enrichment broth as an aid for the isolation of Burkholderia cepacia complex (Bcc) bacteria from water. To allow growth of all nine genomovars, mixtures of two carbon sources had to be used, i.e. L-arabinose/D-cellobiose or L-arabinose/L-threonine. Selectivity was provided by polymyxin B and 9-chloro-9-(4-diethylaminophenyl)-10-phenylacridan (C-390). Following enrichment, Bcc bacteria were isolated on a diagnostic O/F agar supplemented with gentamicin. A preliminary bio-diversity study on 28 surface waters yielded five different genomovars, i.e. B. cepacia(genomovar I), B. multivorans, B. cenocepacia, B. vietnamiensis and B. anthina. Drinking waters did not contain Bcc bacteria. However, the genomovar pattern from a given sample varied with the enrichment broth used.