© 2021 Transactions of Famena. All rights reserved.In the present study, exergy analysis of a ground source heat pump (GSHP) is performed. For this purpose, a horizontal type GSHP test system is installed at Sivas Cumhuriyet University in Sivas Province. GSHP system consists of three main circuits. These are the ground heat exchanger (GHE), the heat pump (HP) and the heating circuit. The temperatures and pressures are measured at the various points of the system. Besides, the mass flow rate of the working fluid circulating in the GHE, heat pump and heat circuit are measured. In addition, power consumption of the compressor and the pumps are measured. Measured data were recorded every minute. The test data used in the calculations are related to the coldest day, December 18, 2016. Exergy loss, exergy efficiency, exergy loss ratio and thermodynamic perfect degree for each element of the system are computed. Exergy efficiency and thermodynamic perfect degree of the system are calculated as 0.27 and 0.86 respectively.