The use of zwitterionic surfactants in advanced oil recovery methods is a current topic, due to its potential application in pre-salt reservoirs. However, there is a possibility that they may adsorb on the surface of the reservoir rocks, which can make the injection of these substances economically unfeasible. The objective of this work was to investigate the static adsorption of the surfactant cocoamidopropyl betaine (CAPB) on the surface of a pre-salt analogous rock (travertine), in fluids of different salinity. Initially, the critical micelle concentration of the surfactant was determined, as well as the surface area, composition and morphology of the rock, and its zeta potential in solution. From these results, a procedure was developed to obtain the isotherms of CAPB adsorption on the travertine surface, at a temperature of 30 degrees C while using micellar solutions prepared in different brines. The results indicated that surfactant increased with salinity. The experimental data were fitted to the classical isotherm models and the best fit was obtained with the Langmuir model. For a better understanding of the adsorption mechanism and the salinity effect, surface speciation simulations were performed in the PHREEQC software. The results suggest that the adsorption is superior in scenarios where there is a greater amount of surface sites resulting from the ionic adsorption of potential determining ions (PDI). From these results, it can be concluded that CAPB adsorption is governed by the ionic composition of the medium and by the impact of these ions on the chemical speciation of the travertine rock surface.