The Streptococcus mutans is one of the main etiologic agents of multifactorial disease of caries. Adhesins like the antigen I / II are proteins of S. mutans and play an important role in caries lesions, even being a target for anti-cavity vaccines. C-phycocyanin (C-PC) is a blue-green heteroprotein which acts as a photosynthetic pigment for cyanobacteria such as Spirulina (Arthrospira) platensis and it has antibacterial effects. Thus, the C-PC could block the adhesins and represent an inhibition the caries process. Verifying the possible docking beween C-PC and adhesion protein antigen I/II of S. mutans in the main goal of this study. We used the PRISM web server (algorithm based on structural matching) for to check the interaction of the C-PC in its complete form (Full) or F chain with adhesion protein (antigen I / II) of S. mutans. The Full C-PC did not interact with the adhesion, while the F chain interacted with a binding energy of -17.12establishing 01 Hydrogen bridge and 139 varied connections (polar, nonpolar, favorable and unfavorable). Thus, the interaction of F chain with adhesion protein of S. mutans indicates a possible anticaries role of C-PC, encouraging continuity of studies in this area.