Criteria for assessing the restoration of decommissioned petroleum well sites in the Cooper Basin, South Australia, have been chosen in conformation with two guiding environmental objectives, namely, the degree of success in establishing long-term minimisation of the visual impact of a site, and in achieving its re-vegetation with indigenous species. The criteria being presented are intended to ensure consistency in assessing environmental repairs carried out against these objectives, by minimising the subjective judgement often associated with such qualitative assessments. In this field guide the descriptions of typical well site restoration outcomes are supported by colour photographs. The photographs are provided as an example only, and do not represent an absolute situation. The preferred assessment process for well site rehabilitation work is based on the concept of goal attainment scaling, in which stakeholders are required to participate in evaluating and seeking consensus on the most important aspects of the goals to be achieved within a particular time frame, and on the range of expected outcomes of the activities undertaken.