The interaction of cytochrome c (cyt c) with phospholipids was investigated using electrochemical. in-situ UV-visible, and FTIR spectrophotometric methods, which showed that the electrostatic interaction between cyt c and cardiolipin (CL) gave a rapid direct electron transfer. This was studied for the effect of charges of lipids on the redox reaction of cyt c and investigated for electrochemical behavior according to the quantity of CL, the accumulation time, pH. temperature, and the stability of the CL layer, The spectroelectrochemical results showed that only the absorption band appearing at 550 nm, which is one of the Q bands, was directly related to the redox reaction of iron ions in cyt c. The kinetic parameters, D-O and k(o) for the electron transfer reaction of cyt c on the lipid layer were determined to be 3.09 (+/- 0.02) x 10(-7) and 2.06 (+/- 0.04) x 10(-3) cm s(-1).