Women's regular use of mammography over a 6 year interval was examined among women aged 45-75 in the Hawaii and Los Angeles Multiethnic Cohort (MEC). The analyses included 81,722 African American, Japanese, Latina, Native Hawaiian, and White females using self-reported mammography history from 1993 to 1998. Ninety-one percent of MEC women reported ever having a mammogram, however only 36% reported regular annual and 48% reported regular biennial mammography over the interval. Mammography was lowest among women who were obese, had a high school education or less, or who were aged 70 and over. Regular mammography use during follow-up was low compared to prior studies reporting on recent mammography. African American, Latina, and Native Hawaiian women had significantly lower annual and biennial mammography use compared to White women even after controlling for age, education, family history, body mass index and hormone therapy indicating that gaps exist in mammography that remain unexplained by known predictors of screening behavior.