Ionic thermocurrent measurements ITC were carried out on NaF doped with 50 ppm Mg+2. The ITC spectrum of a preheated crystal consists of two bands with maximum at 236 and 251 K. The analysis of these bands leads to a migration enthalpy hm of 0.78 and 0.83 eV and to a migration entropy sm of 2.1 and 2.6 K respectively. The value of the ratio sm/hm is comparable to the results of other processes (formation and migration) and is comparable to theoretical expectations.