The desired range of potentials for Li-battery anode materials is a few hundred millivolts relative to Li metal. The zinc-blende-structure compound InSb meets this criterion, and has relatively large capacity as well as ease of electrochemical reaction with Li. The structural transformations that occur in InSb during the initial reaction with Li and on subsequent electrochemical cycling, however, have not been established. The atomic structure of InSb during Li insertion is discussed in the light of first-principles calculations based on local density functional theory for li(x+y)In(1-y)Sb(2), where x(y) is the concentration of interstitial (substitutional) Li.