In this work, VO4 3− substitution for PO4 3− in the Nasicon structured Li3Sc2(PO4)3 was used to enhance its ionic conductivity. The VO4 3− substitution resulted in a homogeneous compound Li3Sc2(PO4)3-x (VO4) x within a wide composition range of 0≤ x ≤ 1.2; further increase in x led to precipitation of the crystalline phases VPO5, V(PO3)3 and ScVO4. Electrical conductivity of the VO4 3−-substituted samples increased with the VO4 3− content, and the sample with x=1.5 exhibited the highest conductivity (8.41×10−3 Sm−1) at room temperature and the lowest activation energy (39.65kJmol−1). The obtained conductivity was two orders of magnitude higher than that of the non-substituted sample and nine times higher than those of the Zr4+ and SiO4 4−-substituted compounds. The present study demonstrates that the VO4 3− anion substitution for PO4 3− is a promising technique to improve ionic conductivity of the Nasicon compound.