Disclosed is a process for the preparation of 1,2-cycloaliphatic diamines from 1,2-aromatic diamines. In one embodiment, the process provides a method for making 1,2-diaminocyclohexane by the reaction of 1,2-phenylenediamine contained in a polar, protic solvent with hydrogen in the presence of a supported rhodium catalyst, ammonia, and an inorganic borohydride, and having enhanced overall conversion and selectivity.