Standard enthalpies of formation, Delta H-f, of the Laves-phases within their solid solutions along the Cr2Nb-Fe2Nb section were measured using drop solution calorimetry for the first time. The enthalpy values change linearly from 2.9 kJ mol(-1) atom(-1) for binary C15-Cr2Nb to -13.6 kJ mol(-1) atom(-1) for C14-Fe2Nb. The obtained values are compared with some earlier results on the binary compounds gathered mostly from ab initio calculations. (C) 2015 Elsevier B.V. All rights reserved.