A new method for preparation of diaminonitrile compounds is reported. In this method primary aliphatic diamine compounds were condensed with two equivalents of benzaldehyde and sodium cyanide in presence of aqueous sodium hydrogensulfite under mild conditions. This method provides an efficient, convenient and practical method for the syntheses of diaminonitrile compounds and the products are easily isolated. The prepared new compounds were characterized by elemental analysis, IR, NMR spectroscopies and mass spectrometry.