The European Parliament (EP) has long been regarded as a positive force for environmental change in the EU, but there has been little detailed empirical scrutiny to determine whether its reputation as a green champion is deserved. Nor has there been any evaluation of the environmental impact of the increase in EP powers under co-decision. These oversights are rectified by an evaluation of the EP's amendments to environmental legislation using typologies that rank them in terms of their level of ecological commitment and importance. EP amendments proposed under three procedures of decision making are compared in order to determine whether recent increases in the EP's powers under the co-decision procedure have affected its ability and willingness to adopt ‘green’ amendments. It is clear that the EP has consistently tried to strengthen environmental legislation but there is some ambiguity as to whether co-decision has been good for the environment.