A method was developed for determining the efficiency calibration curve of HPGe detectors between 26 and 1770 keV. A simple simulation based on the attenuation of gamma-rays in pure germanium was used together with efficiency calibrations performed for three detector-source distances: 5, 12 and 30 cm. The simple simulation model required an energy dependent term with three parameters and these parameters were determined from the fit of the simulated data to the measured efficiency of the detector. The efficiency response of the detector determined this way was then tested with other certified sources to verify the validity of the method. (C) 2009 Elsevier Ltd. All rights reserved.