International standardised test guidelines (TGs) with sensitive endpoints form the basis for hazard identification and characterisation and risk assessment used in the regulation of chemicals. The OECD has developed the Conceptual Framework for the Testing and Assessment of Endocrine Disrupters. The Conceptual Framework ranks, into five levels of increasing biological organisation, the OECD TGs and standardised test methods available, under development or proposed that can be used to evaluate chemicals for endocrine disruption. The Conceptual Framework helps to evaluate the overall strength of the evidence that a chemical may be acting as an endocrine disrupter and to determine additional testing demands.