This study explores the eco-friendly synthesis of silver nanoparticles (AgNPs) using Spirulina extract and their application for cotton fabrics functionalization in order to enhance the photocatalytic and antimicrobial properties. The small size of the synthesized AgNPs was confirmed using Transmission Electron Microscopy (TEM) and dynamic light scattering (DLS), revealing a spherical morphology with an average size of 8.6 nm. The functionalized cotton fabric exhibited excellent catalytic activity, achieving 100 % Congo red (CR) dye reduction at pH 9, and 45 °C for 120 min. Response surface methodology (RSM) optimization using the Box-Behnken Design (BBD) demonstrated a high correlation (R