We are reporting for the first time the synthesis of cadmium nanoparticles assisted by cow urine. These NPs exhibit excellent antimicrobial activity against test micro-organism such as Staphylococcus aureus, Klebsiella pneumonia and Pseudomonas aeruginosa. Also the synthesized nanoparticles show synergetic effectiveness with common broad spectrum antibiotic tetracycline. X-ray diffraction pattern of reaction product confirmed the formation of cadmium nanoparticles.