Abstract This essay critically examines the evolution of the environmental impact assessment (EIA) in Taiwan. The ‘American-style’ EIA was originally introduced in Taiwan as an economic policy-making instrument. During the 1980s, grassroots environmental protests rose. The state first met the popular opposition by denying their professional status, and then sought a more peaceful resolution by upgrading the EIA. In 1994, owing to the combined effects of more accountable parliamentary and environmentalists' lobbying, the EIA was finally codified. Democratization also made the codified EIA more powerful and professional, as environmentalists preferred. The latter part of this essay examines the actual practice of the EIA since 1995, with special attention to some controversial cases. The current EIA failed the proclaimed standard of “science and objectivity,” as politics lurked in the disguise of professionalism.