The crystal of Quinine salt of (+)-0-ethyl O-phenyl phosphorothioic acid belongs to orthorhombic system with space group D24-P21 21 21 and cell parameters a= 29.007 (7)?, b = 14.089 (4)?, c = 6.589 (3)?. There are four molecules ia each unit coll, Z= 4. X-Ray diffraction intensity data are collected on PW-1100 four-circle diffracto-meter, using CuKα radiation. The number of independent diffraction data amounts to 2818, and 2463 are observable reflections. The crystal structure has been determined by direct method (MULTAN-78). The structure parameters were refined by full-matrix least-square method to R=0.082. The absolute configuration has been assigned by direct measurement of 18 enantioner-sensitive Bijvoet reflection pairs. The properties of P-O, P-S bond types were discussed.