This paper depicts the nature of interaction between bovine serum albumin (BSA) and a model amphiphile SDS from conductometric measurements, since no information regarding the mode of surfactant binding to protein from this simple technique is available. The effect of dimethyl sulfoxide (DMSO) on these interactions shall be of some fundamental importance to elaborate further t h e solution behaviour of SDS in Bovine Serum Albumin ( B S A ) . Other thermodynamic parameters of micellization i.e (ΔH0 m, ΔG0 m and ΔS0 m) are also derived in support of the findings.