A nuclear industry worker may receive radiation doses either from external exposure, or from internal exposure (e.g. from inhaled radionuclides). The costs of monitoring of internal exposures in the workplace are usually significantly greater than the equivalent costs for external exposures, and there is therefore a need to ensure that resources are employed with maximum effectiveness. This project will develop methods that could be used to optimise the design and implementation of internal exposure monitoring programmes. Current monitoring programmes will be critically reviewed, the major sources of uncertainty in assessed internal dose investigated, and guidance formulated on factors such as programme design, choice of method/techniques, monitoring intervals, and measurement frequency. The result should be a common approach to the design and implementation of internal dose monitoring programmes throughout the EU.