There is a growing demand for corporate social responsibility in accounting and nonfinancial reports in the form of sustainability reports. Environmental accounting is now advocated in Japan following the initiatives of the government. A part from being required, nor voluntary, a cost-benefit study may encourage more disclosures and reporting guided by a prescribed framework if benefits justify the costs. With Toyota Motors Corporation as subject, this study aims to: (1) describe Toyota's environmental accounting report within the context of Japan's prescribed guidelines; (2) relate the environmental costs to economic effects; and (3) relate environmental costs to the firm's financial performance