The single‐crystal elastic moduli of V3Si have been measured for hydrostatic pressures to 2.5 Kbar and temperatures from 13.5 to 296°K to determine the influence of volume decreases on the anomalousC′ = (C11−C12)/2 shear mode softening in this A‐15 material. Moduli values were obtained by measuring the cw resonance frequencies of three thin specimens that did not undergo at room pressure the well‐known structural transformation exhibited by some V3Si crystals near 20°K. The measurements show all moduli to be linear in pressure.dBs/dP, which is nearly constant at 4 for temperatures down to 40°K, is near 7 at 13.5°K.dC′/dPvaries from unity at 296°K to −5 at 13.5°K, vanishing at near 90°K. These results are compared with those obtained earlier for largeC′‐type shear loads. The possibility of inducing a structural transformation with hydrostatic pressure is discussed.