Marriage records of six raions (districts) of Udmurtia and the city of Glazov (a total of 10,518 records) have been used to calculate marriage-migration parameters. The endogamy indices of the rural and urban Udmurt populations are 0.59 (from 0.48 to 0.76 in individual districts) and 0.29, respectively, and those of the rural and urban Russian populations are 0.33 and 0.47, respectively. The mean ethnic assortativeness values are 1.05 and 0.89 for the rural and urban Udmurt populations, respectively, and 2.13 and 1.44 for the rural and urban Russian populations, respectively. The parameters of isolation by distance for the rural Udmurt population are the following: sigma = 52.4, a = 0.00035, and b = 0.012; those for the urban Udmurt population are 54.1, 0.00020, and 0.010, respectively.