The interactions of bovine serum albumin (BSA) with one anionic, sodium dodecyl sulfate (SDS), cationi c Surfactant cetyl trimethylammonium bromide (CTAB), and a nonio nic triton X-100 (TX-100), at 25 °C in aqueous medi a containing phosphate buffer (20 mM, 0.1 M NaCl, pH 7.0) have been studied through the conductivity me thod. A novel and simple mathematical model was used for ca lculation of mole fractions for each surfactant int eracted with BSA. The results revealed that SDS interact more st rongly than CTAB and TX-100. The results indicated that the SDS, CTAB and TX-100 comprise 98%, 88% and 31% inte raction with BSA, respectively. The results were interpreted on basis of hydrophobic interactions of side chain of surfactant with BSA hydrophobic surf ace patches on BSA.