PURPOSE The purpose of this study was to evaluate a Self-efficacy-based Basic Life Support (SEBLS) program for high-risk patients' family caregivers on cardiac arrest. The SEBLS program was constructed on the basis of Bandura's self-efficacy resources as well as the International Liaison Committee on Resuscitation's "2000 Guidelines for CPR and ECC". METHOD The effect of the SEBLS program on emergency response self-efficacy and emergency response behavior such as BLS (Basic Life Support) knowledge and BLS skill performance was measured by a simulated control group pretest-posttest design. Study subjects were38 high-risk patients' family caregivers (20 experimental subjects and 18 control subjects) whose family patients were admitted to a general hospital in Incheon, Korea. RESULT 1. Emergency response self-efficacy was significantly higher in the experimental subjects who participated in the SEBLS program than in the control subjects. (t=8.3102, p=0.0001). 2. For emergency response behavior, BLS knowledge (t=5.6941, p=0.0001) and BLS skill performance (t=27.8281, p=0.0001) was significantly higher in experimental subjects than in control subjects. CONCLUSION A SEBLS program can increase emergency response self-efficacy and emergency response behavior, and could be an effective intervention for high-risk patient's family caregivers. Long-term additional studies are needed to determine the lasting effects of the program.