Resins are reported to be able to contribute to both the stabilization and destabilization of asphaltenes. Resin adsorption isotherms were carried out on different substrates such as silica particles or asphaltenes and silica-asphaltene fraction A(2) complexes extracted from different Venezuelan crude oils, which either show evidence of precipitation problems (Furrial) or do not (Hamaca and Guafita). Experimental evidence indicates that resins from Furrial crude oil display a much higher tendency to adsorb on the different substrates than resins from the two other crude oils, even on silica particles with the same surface area for all of the resins, thus indicating a higher self-interaction. This self-interaction of resin molecules is shown to be the key factor in determining whether these molecules do or do not stabilize asphaltene colloidal particles against aggregation. The experimental results are interpreted according to a simple repulsion/adhesion alternative model.