Information about the extent and patterns of environmental tobacco smoke (ETS) exposure among Korean Americans is sparse, despite the population's having one of the highest male smoking rates. This paper estimates the prevalence of ETS exposure among Korean American nonsmokers in California, and identifies demographic and other characteristics associated with exposure. Data were collected during 2001-2002 from telephone interviews (in English or Korean) with 2,328 nonsmoking Korean American adults. ETS was encountered by 31% of respondents during a typical day. Exposure was most common in "other locations," where 24% of respondents were exposed, compared with 6% at home and 9% at work. Among those exposed, the greatest dose of exposure occurred at work (6 cigarettes/day) and at home (5 cigarettes/day). Women were four times more likely than men to be exposed to ETS at home (8% vs. 2%, respectively). For both men and women, the odds of exposure were greater among those who were younger, who were unmarried, and whose friends smoked. Additionally, traditional men and bicultural women had greater odds of ETS exposure than those who were more acculturated. Women who were married to smokers, had no children at home, consumed more alcohol, and had no home smoking ban also had greater likelihood of exposure. The results indicate the need for a complete ban of smoking in workplaces and in private homes to prevent exposure, particularly for women whose husbands smoke.