Abstract: The ¹H,³¹P and ¹³CNMR spectral parameters of O-ethyl-O-afyl-N-isopropylamidothionophosphates have been measured in CDCl₃ solutions. It turns out that the ³¹P chemical, shifts decrease with an increasing of electron-withdrawing abilitya of the para-suhstituents Rin the order, MeO>Me>H>Br>NO₂; On the contrary, ¹HNMR shifts of phenyl ring (average shifts of A₂B₃ system) Increase with an increasing of electron-withdrawing ability of the para-substituents R,Viz.MeO<Me<H<Br<NO₂; And ¹³C NMRare without a distinct ofder due to mutual interactions of the two substituents.