The authors report on the incidence rates of breast cancer overall and by histology in a population of unscreened women constituting ∼80% of the total population of women in Denmark from 1973–2002, utilizing the files of the nationwide Danish Cancer Registry. The age-specific incidence rates of breast cancer increased throughout the period, and further, marked changes in the age-specific incidence pattern were observed, where the plateau and change of slope around the age of 46–48 in 1973–1981 shifted to around age 64–66 years in 1994–2002. Age-period-cohort modeling indicated that these changes were not attributable to a birth cohort effect. Although lobular breast cancer incidence increased more than ductal breast cancer incidence, this was only observed in the first decade after the introduction of the ICD-O system in Denmark and probably is attributable to this, whereas we observed no disproportionate changes by histology in any age group from 1988–2002. Thus, previous reports of a disproportionate increase in lobular breast cancer could not be confirmed in a non-screened population, whereas important changes over the past decade in the age-specific incidence pattern of breast cancer particular around the time of menopause were indicated. © 2005 Wiley-Liss, Inc.