► We used different ratios of alginate and k-carrageenan to obtain composite films. ► The composite films were cross-linked in two stages with CaCl2. ► The structures of the composite films were analysed by FTIR, XRD, DTG, TG and SEM. ► Cross-linked composite films show mechanical and swelling properties of hydrogels. ► The 1/3 alginate/k-carrageenan films are suitable for drug delivery applications. The purpose of this work was to prepare an alginate/k-carrageenan composite film cross-linked with CaCl2 that could be used in biomedical applications. The influence of the alginate/carrageenan ratio on the composite films properties was studied in order to establish the optimal composition of the films. Several characterization methods such as: FTIR, XRD, TG/DTG, SEM were used, and the mechanical properties and the swelling behaviour of the obtained composite films were studied.