In this paper an attempt has been made to arrive at a relation between the heat of formation of an intermetallic and the milling energy required for its formation during mechanical alloying. This has been demonstrated in case of B2 intermetallic compounds, namely, NiAl, FeAl, CoAl and MnAl. The milling energy corresponding to the start of formation of the compounds during mechanical alloying of the elemental blends is found to decrease linearly with the heat of formation of the intermetallics, calculated using the Miedema's model. Al3Zr, Ni3Al, Ni3Mn, CoFe, NiTi, Zr3Co are also synthesized in an attempt to test the strength of the hypothesis over a wider range of compounds as well as enthalpy of mixing. An attempt has been made to understand the mechanism of the compound formation. © 2007 Elsevier B.V. All rights reserved.