In principle, trade liberalisation and environmental management are reinforcing. But the simultaneous achievement of these twin socio-economic goals in practice requires trade and environmental policies that complement each other. Evidence presented in this report indicates that neither the agricultural trade nor the environmental policies in OECD countries generally measure up to the complementary standard. Specific problems have already surfaced, and broader conflicts lie in the future. Waiting until the conflicts emerge and deepen to improve policy threatens significant losses to trade and to the environment.