Cost-benefit assessment is used to evaluate the effectiveness of various seismic retrofit strategies to address concerns about earthquake safety and damage to older concrete frame buildings. The benefits of mitigation are quantified in monetary terms by assessing the reductions in risk of building damage (repairs) and occupant fatalities. When evaluated considering repair costs only, the maximum cost of retrofitting that offers a positive rate of return is 10% to 30% of the building replacement value. Since seismic retrofits generally cost more than this, this result suggests that reduced risk of damage and repairs alone does not warrant the expense of retrofitting. However, the added benefits of reduced fatality risks would make retrofitting cost-effective if it costs as much as 60% of the building replacement cost. The cost-benefit approach provides an important tool to evaluate the merits of seismic mitigation in light of competing demands for finite public and private resources.