Beryllium oxide (BeO) displays strong thermoluminescence (TL) together with tissue equivalent properties which underline its application as a TL dosimeter. In the dosimetry of X- and gamma-rays some of the advantages of BeO over other TL materials are its commercial availability, low cost, chemical inertness, non-toxicity (as a ceramic), high sensitivity to ionizing radiations, good reproducibility of response, low fading, absence of low-temperature peaks and moderate energy dependence. Various authors have reported glow curves of BeO it phosphor, whose dominant dosimetric peak lies between about 160 and 200 degrees C. The position of this peak, however, depends upon the type of the radiation used for exciting the phosphor. Although fading of TL is nominal when kept in the dark, the gamma-exposed BeO phosphors fade faster when exposed to ambient light. When exposed to gamma-radiation, these phosphors exhibit linearity from a minim um of about 1 mrad (1 rad = 10(-2) gray) up to approximately 10 rad, above which there is supralinear behaviour, and the concentration of impurity ions in BeO is reported to expand the linearity region. Ceramic samples have been reported to exhibit a roughly flat response when exposed to X-rays of 30-115 keV and gamma-rays of Co-60. Because their response to thermal neutrons is negligible compared to the gamma-response, the use of BeO has been suggested to measure the gamma-component in the (n, gamma) mixed fields.