This case study considers the process through which the civil society of Ilo - a city located in the southern part of Peru - guided by the developmental NGO Labor, became a real influence in the environmental attitude and corporate social responsibility of the Southern Peru Copper Corporation (SPCC), one of the main copper producers in the world. One of the high points of this case study is from 1992, when Labor and Ilo's Municipal government won a suit against SPCC in the Second International Water Tribunal in Amsterdam. This event, having exposed SPCC's negative environmental impact to an international forum, was a turning point in its social responsibility behaviour. Afterwards, the mining company started a coordinated plan lead by the Peruvian Government to accomplish a set of environmental standards to reduce its air and water pollution.