SUMMARY: d-Glucarate is transported into Escherichia coli K12 by an inducible system at an apparent rate of 7 to 15 nmol min-1 (mg dry mass)-1. The apparent Km for uptake is 16 μm. The system is induced by growth on glucarate or glycollate. Galactarate competes with glucarate for the uptake system. A mutation (garA) was isolated in which activities of glucarate transport and glucarate dehydratase and the ability to grow on glucarate or galactarate are all impaired. The mutation maps at min 16. Another mutation of indistinguishable phenotype is probably a deletion of the genes garB and ton A at min 3·5.