A number of previous studies have documented a fairly high level of marital homogamy in Norway. Most of these studies, however, have been local and ethnographic, or based on national data measuring homogamy within a limited time period. This study is based on a sample of 129 651 individuals from the 1980 Census. From this data bank, a sample of couples is constructed. Patterns of educational homogamy across five ten-year cohorts, born between 1900 and 1949, are compared. The results show a decline in educational homogamy across these cohorts, both in absolute terms and when controlling for the general increase in educational level during the period.