Pseudomonas aeruginosa produces exoproducts correlated with its pathogenicity. One of these virulence-associated traits is the surfactant rhamnolipid. The production of alginate and lipopolysaccharide (LPS) are also of importance for P. aeruginosa virulence. The product of the algC gene (which is involved in alginate production through its phosphomannomutase activity and in LPS synthesis through its phosphoglucomutase activity) participates in rhamnolipid production, presumably catalyzing the first step in the deoxy-thymidine-diphospho-L-rhamnose (dTDP-L-rhamnose) pathway, the conversion of glucose-6-phosphate to glucose-1-phosphate. Other structural alg genes, encoded in the alg operon, are not involved in rhamnolipid nor LPS production. These results show that the AlgC protein plays a central role in the production of the three P. aeruginosa virulence-associated saccharides: alginate, LPS and rhamnolipid.