Potential political biases against environmentalists in the mediation process are examined: (1) the possibility that the congenial atmosphere created by mediators serves to disarm and co-opt environmentalists; (2) a power imbalance between the two parties may yield unfair concessions from environmentalists to prodevelopment interests; and (3) the possibility that the mediation process itself tends to redefine environmental issues in a way that favors prodevelopment interests. Suggestions are discussed for avoiding the bias factor in mediation. It is suggested that in certain disputes, (for example, nuclear power, where compromise is not appropriate) the problem of definitional bias may not allow for the discussion of workable solutions. The mediator should keep in mind that each issue involves a mixture of negotiable and nonnegotiable issues. Since the mediator desires to keep discussion at a reasonable level, bias often emerges not necessarily as a result of any personal political bias on the part of individual mediators, but as a function of the inherent limitations of the mediation process. It is suggested that mediation works best in disputes that are primarily local and that do not involve basic value conflicts or structural choices. It is recommended that environmentalists concentrate on building greater sources of formal political power. Seventy-seven footnotes are provided.