The study aims to develop a legal principle that can be applied either within the constitutional framework of International Economic Law, or as a decision-making tool in the dispute settlement of the WTO where economic, social and environmental factors are in tension detrimentally to each other. The concept of balance constitutes a constitutional fundamental in handling with the systemic relationships between three inseparable, equally legitimate interests. The integrative process of globalisation challenges international law to develop coherent approaches that meet goals and common interests of the international community. The principle of balance is therefore oriented conceptually on common values, though retaining in essence the neutrality and objectivity of a legal principle. The paper suggests a balance test as a practically applicable decision-making instrument that should keep an overall integrated, systemic approach, yet with due regard to individual needs existent within any system. Furthermore, it is suggested that active co-operation and mutual harmonic complementation should be fostered between economic, social and environmental factors as they serve the same common values such as human rights and the environment.