Starting with a strain containing a malK-lacZ fusion, a series of lambda plaque-forming phages which carry varying amounts of the malE,F operon have been isolated. We have used these phages to construct a deletion map of the malE,F operon. The construction of this deletion map has led to the identification of a new gene, malG. The malG gene is located distal to malF. The malG gene product is a protein required for the active transport of maltose and maltodextrins.