It has been demonstrated clearly that the use of regular screening mammography reduces mortality among women ages 50 years and over. The primary objective of this study was to investigate factors associated with repeat mammography participation. A random sample of women ages 50-75 years residing in four Washington State counties was surveyed by telephone during mid-1989. The Health Belief Model was used as a conceptual framework for the analysis. Three groups of women with different mammography experiences in the previous 5 years were compared: (a) nonusers; (b) onetime users; and (c) repeat users. The survey response rate was 72%, and the study sample included 1357 women. One time users were more likely to have health insurance coverage, to visit a gynecologist or other primary care physician regularly, and to believe mammography is more effective than breast self-examination; they were less likely to think that at least 1 in 10 women are diagnosed with breast cancer or that mammography is inconvenient to obtain than were nonusers. Factors associated with repeat versus onetime use included routinely visiting a gynecologist, thinking the lifetime risk of breast cancer is at least 10%, and perceiving a high personal susceptibility to disease. Women who perceive themselves as being vulnerable to breast cancer are more likely to report repeat mammograms. Visiting a gynecologist regularly is associated with repeat as well as initial mammography use. These factors could be considered as the focus of promotional efforts moves from encouraging women to obtain their first mammogram to encouraging repeat use.