The scope of this study is the implementation of a Solid Waste Minimization Plan (SWMP) for “Oilsa”, an Oil Company with operations in the Amazonian Region, Ecuador, which is a very sensitive area. First, the current situation of the field was evaluated in terms of the social, economical, political, legal and environmental aspects, as well as the waste management practices. Second, a Waste Prioritization Tool was developed to undertake a quantitative evaluation under local conditions in order to identify the most critical waste to be handled. According to the criteria proposed, the drilling fluids were found to be the most critical waste, despite its non-hazardous classification by the Ecuadorian Legal framework, followed by thermal residues from Hazardous Waste Incineration, oil filters and lead-acid batteries. Methods of management based on the latest international common practices were presented. It is suggested that a cost/benefit analysis and local conditions assessment should be carried out as important key factors in determining the most sustainable management practices.