Twenty keV Li+ was implanted at room temperature into p- and n-conducting single crystalline CuInSe2 at fluences of 3.2 x 10(15) and 3.2 x 10(16) cm(-2), respectively. The lithium depth profiles were measured using the neutron depth profiling technique. The diffusional deviation of the profiles from the ballistic expectation was simulated by a numerical computer calculation. From these examinations it is concluded that (a) lithium suffers considerable radiation-enhanced mobility during the implantation process, (b) the radiation-enhanced Li diffusion depends somewhat on the conductivity state of CuInSe2, (c) the radiation-enhanced Li diffusion decreases with increasing implantation fluence, (d) whereas at the lower fluence, Li shows some thermal mobility, the latter is negligible after high fluence implantation. The diffusional redistribution can be described in all cases reasonably well by depth independent diffusion without trapping, and insofar differs from previous examinations of hydrogen in CuInSe2.