Context: Octogenarians are the fastest growing segment of the population and little is known about the results of cardiopulmonary resuscitation (CPR) after in-hospital cardiac arrest in this population. Objective: We sought to investigate the clinical benefit and cost-effectiveness of CPR after in-hospital cardiac arrest in octogenarians. Main Outcome Measure: Years of life saved. Design: Effectiveness data were obtained from a review of 91,372 hospital discharges from January 1st, 1993 until June 30th, 1996. Cardiac arrest was reported in 956 patients. The study group consisted of 474 patients ≧80 years old. CPR costs included equipment and training, physician and nursing time and medications. Post-CPR expenses included in-hospital true cost, repeat hospitalizations, physician office visits, nursing home, rehabilitation, and chronic care hospital costs. Life expectancy of the patients who were still alive at the end of the study was estimated from census data. A utility of 0.8 was used to calculate quality-adjusted-life years saved (QALYS). We used a societal perspective for analysis. Results: The study population was 86 ± 4.8 years old (range 80–103), and 42% were male. Fifty-four patients (11%) were discharged alive, 35 to a chronic care facility and 19 to their home. Assuming that a cardiac arrest without CPR has 100% mortality, 12 octogenarians required treatment with CPR in order to save one life to hospital discharge. Similarly, 29 octogenarian patients with cardiac arrest have to be treated with CPR to net one long-term survivor (mean survival 21 months, with a range from 9 to 48 months). The cost-effectiveness ratio, after estimating the life expectancy of octogenarian survivors, was USD 50,412 per year of life saved, and USD 63,015 per QALYS. However, a utility of 0.5 yielded a cost of USD 100,825 per QALYS. Conclusion: In comparison with other life-saving strategies, CPR in octogenarians is effective. The favorable cost-effectiveness ratio is highly dependent on the patients’ preference for quality rather than quantity of life, as expressed by the utility assumptions.