The fosmidomycin derivative FR900098 represents an inhibitor of the 1-deoxy-D-xylulose 5-phosphate (DOXP) reductoisomerase with potent antimalarialactivity. Prodrugs of FR900098 with increased activity after oral administration were obtained by chemical modification of the phosphonate moiety to yield phosphodiaryl esters. One diaryl esterprodrug demonstrated efficacy in mice infected with the rodent