The heat capacities of vitreous and crystalline GeSe2 as obtained by relaxation calorimetry from 2 to 25 K are reported. Focus is given to the effect of the structure on the heat capacities and on the boson peaks observed for both vitreous and crystalline GeSe2 below 4 K. The accuracy of the commercial instrument used is considered by comparing the results obtained with earlier heat capacities determined by adiabatic calorimetry. (c) 2006 Elsevier B.V. All rights reserved.