We have evaluated the nature of the prevailing molecular interactions in solutions of lectins (Con A and WGA) and surfactants (sodium dodecyl sulphate, SDS, and triton X-100, TX-100) by use of fluorescence and impedance spectroscopies. By collecting the fluorescence spectra we showed that while the maximum of emission of the native lectin was at 336nm [360nm] for Con A at 19mM [WGA at 29mM] a hypsochromic shift is observed in its interaction with either surfactant. Also, by examining the structural residue of both proteins we have been able to confirm that when high molarities of the surfactants were used, the structural residues of tryptophan were lost, since the denaturation process causes the quenching of the corresponding luminescent properties. While for Con A this denaturation process occurs at 10´10^-1M [10´10^-3M] of SDS [TX-100], for WGA the corresponding concentrations were lower (10´10^-4M for SDS and 5´10^-5M for TX-100). We then see that the non-ionic surfactant (TX-100) has a higher capability of modifying the architectural structure of both lectins. By use of electrical impedance spectroscopy, we have examined how the relaxation frequency of Con A varies in the presence of TX-100 and SDS. If, as expected, in the limit of low concentrations of surfactants there is a convergence of the curves of relaxation frequency as function of surfactant concentration (in an indication that the lectin response is dominant), at higher concentration an accentuated separation of curves is observed, since the ionic character of SDS contributes to the increase in the values of the relaxation frequency. In this manner, we have been able to establish the applicability of impedance spectroscopy as a convenient tool for the analyses of molecular interactions and characterization of surfactant-protein associations.