Measurements of the resistivity in the normal state of lithiated YBa2C
u3O7-3x, are reported. At low x(Li)-values (<0.06), lithium substitute
s copper of the CuO2 planes. The samples are metallic; a progressive l
ocalization of the charge carriers is observed rn the intermediate con
centration range, lithium occupies both copper sites planes and chains
which leads to a two-phased system; the slope d rho/dT is nearly inde
pendent of temperature. In the concentrated range, lithium is in the c
hain site. The resistivity behaviour is well described by the simple r
elation rho = rho(0)T(0)/T with rho(0)T(0) = 10 Omega.cm.K, a result w
hich is consistent with a single YBCO6-type phase.