The intermetallic compound InSb with a zinc blende-type (diamond) structure has been investigated as a host structure for lithium. After one break-in cycle, it appears that lithium can be inserted electrochemically into the structure in a two-step process to the approximate composition Li2InSb. X-ray diffraction analysis showed that further lithiation of Li2InSb displaces In from the structure to yield a closely related Li3Sb-type structure. The electrochemical reaction that occurs between 1.2 and 0.5 V is reversible. The cubic unit cell expands isotropically by only 5.6% upon Li insertion to the end-member Li2+xIn1-xSb at x approximate to 0.5. This finding has implications for developing commercially attractive intermetallic insertion electrodes with zinc blende-type structures for lithium-ion batteries.