Barriers to screening and early detection often result in cancers in low-income and minority women diagnosed at stages too advanced for optimal treatment. This randomized controlled trial examined whether a personalized form (PF) letter containing generic cancer information and a personalized tailored (PT) letter containing minimally tailored individualized risk factor information based on medical records data affected breast and cervical cancer screening among 1574 urban low-income and minority women. The personalized form-letter group was significantly more likely to schedule a screening appointment and to have undergone a Pap test and mammography within 1 year after the intervention than were the tailored letter and control groups (P<0.001 for all comparisons). Personalized tailored letters that contain individualized cancer risk factor information may decrease the likelihood of receiving cancer screening among medically underserved low-income and minority women, but personalized form letters that contain generic cancer information may improve these rates in this disadvantaged population.