The hybridization effect on two important quantities, chemical hardness and chemical potential, has been studied by HF-SCF theory using a 6-31G basis set. The maximum hardness principle has been tested for C-C and C-H symmetric stretching with positive and negative mean amplitudes of vibration. For the above study, three different types of hybrid orbital molecules, CH 4 , C 2 H 6 , C 2 H 4 and C 2 H 2 , have been used.