Korean men and women have the highest current smoking rates across all Asian ethnic subgroups in the United States. This is a 2-arm randomized controlled study of a culturally adapted smoking cessation intervention. The experimental condition received eight weekly 40-min individualized counseling sessions that incorporated Korean-specific cultural elements, whereas the control condition received eight weekly 10-min individualized counseling sessions that were not culturally adapted. All participants also received nicotine patches for 8 weeks. One-hundred nine Korean immigrants (91 men and 18 women) participated in the study. The rate of biochemically verified 12-month prolonged abstinence was significantly higher for the experimental condition than the control condition (38.2 vs. 11.1 %, χ (2) = 10.7, p < 0.01). Perceived family norm significantly mediated the effect of cessation intervention on abstinence. Smoking cessation intervention for Korean Americans should be culturally adapted and involve family members to produce a long-term treatment effect.