dTDP-L-rhamnose is the activated sugar that is used in the synthesis of capsular polysaccharides in gram positive bacteria and O-antigens of gram negative bacteria. This molecule is synthesized by a series of four enzymes in the dTDP-L-rhamnose biosynthetic pathway. The last enzyme of the pathway, dTDP-4-dehydrorhamnose reductase, catalyzes the production of NADP and dTDP-L-rhamnose from NADPH and dTDP-4-dehydro-6-deoxy L-mannose. There are 6 molecules in the P21 asymmetric unit of the 2.65 Å resolution crystal structure of the dTDP-4-dehydrorhamnose reductase from Bacillus anthracis. Six subunits form two head-to-head trimers. Larger Rossmann-fold catalytic domains are at the oligomerization interface in each timer, whereas smaller hood domains of one timer face these domains in another trimer. Pairwise structural alignment of the subunits reveals movement of the hood domains. When two trimers are superimposed, the biggest rmsd value is 0.9 between two individual chains from each of the trimers. All six subunits have NADP bound.