Simple cubic perovskite La0.67-xLi3xTiO3 (x = 0.06-0.15) with disordered arrangement of the A-site ions was prepared by quenching from 1350 degrees C into liquid N-2 : and tetragonal, doubled perovskite (a = a(p), c approximate to 2a(p)) with alternate arrangement of La-rich layers and Li-vacancy-rich layers along the c-axis, by annealing the quenched pellet at 800 degrees C for 3 days. No extra lines due to superstructures other than the tetragonal polymorph were observed. Contrary to the expectation that the Li-vacancy-rich layers would be more favorable for fast conduction, the ordered samples (the parameter of order : S approximate to 0.55-0.7) were found to have lower conductivity than the disordered samples in the range x > 0.08. A maximum bulk conductivity of 1.53 x 10(-3) S cm(-1) at 25 degrees C, which is the best yet reported for known perovskite solid solutions, was found for the disordered sample with x = 0.121 a lower conductivity of 6.88 x 10(-4) S cm(-1), was found for the ordered sample (S approximate to 0.6). The lower conductivity is attributed to an increase in activation energy for ionic conduction that is associated with a decrease in the lattice parameter a of the primitive cell.