Metal nanoparticles—specifically copper and silver—and their hybrid structures possess unique optical, physical, and chemical properties, leading to their widespread application across various industries, particularly in the field of functional textiles. Among the available synthesis approaches, the reduction of metal salts in the presence of stabilizing agents allows for precise control over particle size; however, "green synthesis" is highly preferred due to its avoidance of toxic solvents and reagents, as well as its superior environmental compatibility. In this study, the *in-situ* green synthesis of silver/copper hybrid nanoparticles directly onto a cotton fabric substrate was investigated. Maltose, a natural disaccharide, served as the reducing agent, while ascorbic acid (at a constant concentration) was employed to control particle dimensions and provide protection. To determine optimal conditions, the concentrations of the silver and copper precursor salts were varied. The physical, structural, and morphological characteristics of the samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and reflectance spectroscopy. Furthermore, the wetting behavior and physico-mechanical properties of the fabrics were evaluated through wicking tests, contact angle measurements, tensile strength analysis, abrasion resistance testing, and flexural rigidity (stiffness) assessments. The results indicated significant differences among the various treatment conditions. The optimized sample (A1C1M1) exhibited the highest degree of hydrophobicity and water-repellent properties—due to the formation of nanoparticles with an average size of 77 nm uniformly distributed across the fiber surface—while maintaining the textile's desirable mechanical properties.