An analysis of surname frequencies was used for the study of population structure. The surnames in the register of the parish of Los Teques, Venezuela, from 1790 to 1869 were classified in three classes, frequent, intermediate, and rare. Using the surnames of the male spouses it was found that a relationship exists among the surname class and consanguinity, place of birth and marriage with a woman belonging to an equal surname class. The individuals with frequent surnames have a higher probability to belong to a consanguineous marriage, of being born in Los Teques and of having married a woman of the same surname class than the individuals with rare surnames.There is evidence that “endogamic clusters” exist within the frequent surnames, since eight surnames composed a fifth of the total sample. It is believed the surname frequencies could be used as indicators of inbreeding, endogamy and migration
