Data from marriage records of the city of Belgorod for 1960, 1985, and 1995 have been used to determine some parameters of population structure in this city. The coefficients of correlation with respect to age of marriage between spouses in the couples contracting marriages in these years were 0.74, 0.62, and 0.80, respectively. Women of reproductively unfavorable age (under 20 or over 30 years) accounted for 5.5, 0.83, and 19% of all women contracting marriages in these years, respectively. The proportions of interethnic marriages in these years were 16.9, 14.9, and 15.6%, respectively. The percentage of Slavs decreased from 99 to 97% during the 35 years studied, whereas the proportion of Russians insignificantly increased (from 90.4 to 91.4%). The proportion of Caucasian ethnic groups increased by six time (from 0.3 to 1.8%), and that of other non-Slavic ethnic groups increased by almost two times (from 0.7 to 1.2%). The marriage convergence (K) with respect to ethnicity (0.095, 0.106, and 0.090 in 1960, 1985, and 1995, respectively) was lower than that with respect to education (0.296 and 0.350 in 1985 and 1995, respectively) or occupation (0.212 and 0.231 in 1985 and 1995, respectively). The maximum coefficients of ethnically, educationally, and occupationally assortative marriage have been found, respectively, in ethnic minority groups (A' = 20%); in persons with higher and primary education (A' = 37.5 and A' = 49.9%, respectively); and in the military officers/soldiers, engineers, healthcare professionals, and researchers (the respective A' values are 65.6, 32.2, 31.5, and 39.8%).