The aim of this study is to develop chitosan-based adhesives and to characterize their shear strength. The desirable features of such adhesives are biodegradability, biocompatibility, non-toxicity, and anti-microbial properties. Various eco-friendly polyanionic polysaccharides, acids, and plasticizers, in single or multiple formulations, were associated with chitosan. The resulting crosslinked polymers were glued on some chemically treated aluminum adherends. The shear strength of these formulations was measured with the 'double lap-joint' bonding method, as it features a low-peeling effect. The shear strength of 40.8 MPa obtained for formulations containing chitosan and glycerol plasticizer was the most significant finding in this study. This value is equivalent to that obtained with a synthetic adhesive used in industry.