An ionophore-nucleotide conjugate is proposed as a new class of nucleoside prodrug. Specifically, 5′-phosphate diester derivatives of the anti-HIV agents AZT (3′-azido-3′-deoxythymidine) and DDU (2′,3′-dideoxyuridine) were prepared with a crown ether as the phosphate masking group. Biological testing of these prodrugs revealed they had moderate anti-HIV activity.