Aryl nucleoside H-phosphonates, a new type of derivatives of controlled reactivity, proved to be superior intermediates, compare to mixed anhydrides, in the synthesis of phosphate analogues bearing P-N or P-S bonds. In this review, a short account of chemistry and some mechanistic aspects of aryl H-phosphonates, together with selected applications of this class of compounds in the synthesis of nucleotides and their analogues, is presented.