The official Japanese recommendation for breast cancer screening is physical examination by a physician, in contrast to US recommendations of mammography. In this analysis of breast cancer screening, the authors used Japanese data in a cost-effectiveness model to compare the following five strategies: (1) no screening (N); (2) physical examination alone (PE); (3) mammography (MG); (4) PE followed by MG if PE findings were abnormal (PE----MG); and (5) PE combined with MG for all screened women (PE + MG). None of these programs would save medical expenditures. The total discounted net costs per patient (in US dollars) were as follows: N, +54; PE, +412; MG, +517; PE----MG, +340; and PE + MG, +731. The number of years of life saved per cohort of 100,000 asymptomatic Japanese women would range from 708 (PE----MG) to 3724 (PG + MG). The additional cost of each strategy (compared with N) per additional year of life would be +49,700 for PE, +40,400 for PE----MG, +14,300 for MG, and +18,000 for PE + MG. The least costly screening option (PE----MG) does not have the lowest cost per additional year of life saved (MG does). MG would be preferable to the current Japanese recommendation of PE alone.