[en] Occupational exposures of radiation workers due to external sources of radiations in three major categories of work i. e., Pakistan Research Reactors (PRR), Isotope Production Plant (IPP) and Applied Health Physics (AHP) were measured using thermoluminescent dosimeters and reported in this article for the period 2003 to 2007. It has been found that average annual effective doses remained in the range of 1.52-3.36 mSv, 0.91-3.19 mSv, and 0.24-2.63 mSv at PRR, IPP, and AHP, respectively, during the said period. All doses are well below the annual dose limit of 20 mSv and found to be comparable with the doses received by the workers in other parts of the world. No over exposure case has been identified during the period. It can be concluded that radiation workers of PINSTECH are well trained and observe the principles of radiation protection. Doses are analogous with UNSCEAR report and other countries of the world, in the same fields. (author)