This publication is intended to support those working in the field of diagnostic radiology dosimetry, both in standards laboratories involved in the calibration of dosimeters and those in clinical centres and hospitals where patient dosimetry and quality assurance measurements are of vital concern. This code of practice covers diverse dosimetric situations corresponding to the range of examinations found clinically, and includes guidance on dosimetry for general radiography, fluoroscopy, mammography, computed tomography and dental radiography. The material is presented in a practical way with guidance worksheets and examples of calculations. A set of appendices is also included with background and detailed discussion of important aspects of diagnostic radiology dosimetry.