A 5,800-bp (base pair) HindIII-EcoRI DNA fragment containing malT, the positive regulator gene of the maltose regulon, and most of malP, the structural gene for maltodextrin phosphorylase, was cloned into pBR322. A sequence of 802 bp was established in a DNA segment containing the promotor for malPQ and the promoter for malT. A total of 611 bp separates the initiation codons for these two genes, which are transcribed in opposite directions. The malT product was identified as a 94,000 dalton polypeptide.