A total sample of 31 837 marriage records made in 13 raions (districts) of Tatarstan in 1990-2000 have been used to determine the endogamy index and parameters of Malecot's isolation by distance model. The endogamy index varied from 0.45 in Pestrechinsky raion to 0.74 in Aktynashsky raion. The parameters of Malecot's isolation by distance model varied in Tatars as follows: random inbreeding, from 0.00014 to 0.00076; root mean square migration, from 46 to 110 km.