Many companies are adopting environmental performance programs that aim to go beyond regulatory compliance and provide greater environmental protection. How effective are they in doing so? This Article collects and surveys the empirical studies of environmental performance of these programs and presents a picture of mixed results. When companies adopt environmental management systems, their regulatory performance and nonregulated environmental impacts often improve. There is little empirical support, however, for the proposition that these systems are associated with design and implementation of greener products or processes. When companies adopt voluntary environmental performance standards, the evidence is mixed; it seems to suggest that these standards are not associated with improved performance. Yet a qualification is needed here: both the company programs and the empirical studies are relatively new and these results may well change as the programs become more institutionalized within the companies, and the studies have access to better data.