Despite rapidly increasing incidence rates of breast cancer, recent immigrants such as Korean-American (KA) women report disproportionately lower utilization of screening tests compared with other ethnic groups. Early screening of breast cancer for this population may be greatly facilitated by indigenous lay health workers (LHWs). We conducted an intervention trial with a 6-month follow-up. Trained LHWs recruited 100 KA women 40 years of age or older who had not had a mammogram during the past 2 years. Ninety-three completed follow-up questionnaires. A 120-min, in-class education combined with LHW follow-up counseling and navigation assistance through the health care system was provided. Rates of breast cancer screening behaviors significantly increased at 6 months (P less than 0.001); changes between pre- and post-intervention were 31.9% for mammography, 23% for clinical breast examination and 36.2% for breast self-examination. Modesty toward screening significantly decreased over time, but we did not find any significant differences in breast cancer knowledge and beliefs before and after the intervention. Results support the efficacy of this neighborhood-based, culturally sensitive intervention. Further research should seek to replicate these findings and to incorporate more self-care skills such as health literacy when designing an intervention program for linguistically and culturally isolated immigrant women. (Contains 4 tables and 1 figure.)