The valuation of biodiversity is a fundamental step in conservation. The useful framework for analysing the economic value of biological resources is that of total economic value (TEV) and TEV comprises both use and non-use values, the former related to an actual use made of the resource, the latter to a willingness to pay for the resource independently of any use made of it. There are several valuation approacher in environmental economics literature. However, stated preference approach should be introduced for valuation of biodiversity because it can estimate non-use value as well as use value. Contingent Valuation and Conjoint Analysis are representative methods in stated preference and Conjoint Analysis can be more useful for valuation of biodiversity. Futhermore, the combination of ecology and economics to assess biodiversity leads to an integrated framework. Thus, interdisciplinary work is required, involving both economists and ecologists transferring elements or even theories and models from one discipline to another and transforming them for their specific, mutually consistent purpose.