Li3xLa(1-x)VO4(0 less than or equal to x less than or equal to 0.3) solid solutions have been obtained by thermal treatment of lanthanum and lithium nitrates with V2O5 in the temperature range 700-980 K. The crystal structure of these single phases has been refined by the Rietveld analysis of powder X-ray diffraction data. The structure refinement of Li0.15La0.95VO4 by neutron diffraction has been also achieved at 295 K. This compound adopts a distorted monazite-type structure : space group P2(1)/n, a = 0.7047(1) nm b = 0.7283(6) nm c = 0.6726(8) nm, beta = 104.86(1)degrees, Z = 4.