Ultrafine fibers are gaining attention for their unique properties and wide-ranging applications. Among production techniques, electrospinning stands out for its cost-effectiveness, simplicity, and control over fiber structure and diameter. This study reports for the first time the development of ultrafine fibers using zein, a renewable protein, with the addition of fucoidan, a bioactive polysaccharide from brown algae, through electrospinning. Polymeric solutions of 30 % zein and varying concentrations of fucoidan (0 %, 25 %, 30 %, 35 %) were produced, with viscosity and electrical conductivity analyzed. Solutions with 25 % and 30 % fucoidan showed higher viscosity, while conductivity remained relatively stable. The hydrophilic nature of the solutions, indicated by contact angle analysis, favors cell adhesion and proliferation. Fourier transform infrared and X-ray diffraction analyses confirmed the material characteristics and amorphous nature of the fibers. Ultrafine fibers distribution averaged 540 ± 130 nm, with those incorporating 25 % and 30 % fucoidan forming ribbon shapes and smaller diameters (234 ± 54 nm and 276 ± 54 nm), which suggests improved fiber structure, potentially enhancing biological activity. Cytotoxicity tests on mouse fibroblast cells showed no toxic effects after 24 and 48 h, supporting the feasibility of further biological studies, including the potential use of these fibers as skin healing adhesives.