Twenty-five years ago, ecological assessments were being performed by different organizations, using different principles and methods, with little or no communication between different groups and no means for reconciling conflicts and inconsistencies between assessment methodologies. The recognition by practitioners of environmental assessment of the need for a unifying conceptual framework stimulated the development of today's Framework and Guidelines for Ecological Risk Assessment (ERA). This paper discusses the success of ERA as a process for linking environmental science to decision making, using 3 recently published case studies involving establishment of baseline ecological risks at a contaminated site, probabilistic assessment of regional risks of pesticide use, and regulation of pharmaceutical product manufacture. Some promising future directions in ERA are briefly discussed, and 3 critical challenges to future success are identified.