An HPGe detector‑based shadow shield bed whole body counter has been developed for internal contamination monitoring of radiation workers. The system is calibrated for the measurement of internally deposited radionuclides which emits photon energies >100 keV. Its performance characteristics are compared with NaI(Tl) detector‑based whole body counter. It is observed that due to superior energy resolution of the HPGe‑based system, identification and quantification of internally deposited radionuclides in workers is superior than NaI(Tl) detector‑based system. The ⁴⁰K contents of 15 persons were measured using this system. It is found that the total body potassium varies from 0.82 gk kg⁻¹ to 2.6 gk kg⁻¹ of the body weight.