We conducted a population-based study of consanguineous marriages in Jordan.

About two thousand households were interviewed.

First cousin marriages were encountered in 32.03%, second cousin in 6.8%, distant relation in 10.5%, and no relation in 50% of all marriages, respectively.

Inbreeding coefficients were compared with those of other countries.

The most important variables affecting inbreeding were social tradition, religion, education, and place of residence-urban vs. rural.

Secular trends appear rather stable since the early decades of the twentieth century, especially for first cousin marriages.