Health and environmental scientists, professional risk managers and the general public strongly disagree about the seriousness of many risks. Most members of the public are concerned about long-term effects of risks, equity and fairness issues, lack of personal control, and the pace of technological diffusion into their cultural environment, whereas professional toxicologists and risk managers focus on the task to minimize the probability of adverse effects caused by a potentially hazardous agent or activity. To bridge the gap between the professional mandate and the public perception of risk, two-way communication has to be initiated between scientists, risk managers, interest groups, and representatives of the affected public. This dialogue should serve three major functions:to facilitate understanding of different risk perspectives among scientists, regulators and stakeholders as well as groups of the public; to enlighten all these constituencies about different rationales for dealing with toxicological risks; to develop appropriate procedures for conflict resolution. A prerequisite for a successful communication is the willingness of each group to respect the perspective of all the other participating groups and to include their concerns into the decision making process. The conference paper reviews the literature on the three main functions of risk communication: message recognition, mutual understanding and respect as a prerequisite for trust building and resolution of risk-related conflicts. The paper discusses the structure of the communication process from a descriptive and a normative point of view and draws on empirical studies about risk perception and communication. The argument will be made that risk cannot be understood as a monolithic concept that penetrates different research disciplines and risk management camps. Risk should rather be seen as a mental instrument that allows prediction of future hazards and facilitates risk reduction measures. Due to the inherent ambiguity and uncertainty of conceptualizing risk, different concepts of risk compete with each other and rely on different rationales. The main goal of risk communication is, therefore, integration of different concepts of risks, in particular with respect to setting priorities in risk reduction and mitigation. The author will introduce a recent initiative by the OECD Chemical Risk Group to accomplish this goal.