It is shown that an international network of ESR dosimetry laboratories can exchange alanine samples for precise interlaboratory calibration in the absorbed dose range 0.01–100 kGy. For the experimental verification the alanine/ESR dosimetry laboratories and calibration centers of both the GSF-Forschungszentrum fur Umwelt und Gesundheit, Neuherberg, and the Istituto Superiore di Sanità (ISS), Rome, were mutually acting as a partial network. A blind test, together with the National Physical Laboratory (NPL), Teddington, UK, revealed agreement between the NPL administered doses and the doses reported by GSF and ISS within ±1%.