This paper analyzes the intention to use (pure) biodiesel under different scenarios. A model of the intention to use biodiesel has been developed based on the Theory of Planned Behavior (TPB) and estimated using data from a survey conducted in Spain in 2010. Results show that the intention to use biodiesel depends on the price and availability of the biodiesel in the market. Even when biodiesel would be available in the market at the same price and widely spread through the current fuelling network less than 50% of all motorists would purchase biodiesel. These percentages diminish when consumers are required to pay higher prices or change behavior.