The formation of novel biocompatible multilayer films based on the alternate deposition of CHI and ALG was investigated for the first time by QCM-D and FTIR-ATR. A linear increase of the thickness was found during the film build-up. GLUT was used to crosslink the films terminated with either CHI or ALG. A change in the QCM-D signal was observed just in the first case, indicating that crosslinking only takes place in the top CHI layer. The evolution of the dissipation factor during crosslinking was modelled with a first-order kinetics; this reaction was found to be faster for chitosan terminated films with a lower number of multilayers. It was also found that more robust films could be produced by crosslinking the intermediate CHI layers during the build-up.