This invention is directed to a broad spectrum antimicrobial composition which comprises a mixture of an iodopropynyl compound in combination with 2-(methoxycarbonylamino)benzimidazole and, where desirable, an algicide said mixture provided in an amount sufficient to protect a substrate from attack by one or more organisms. The composition can be used broadly in industrial systems and more particularly with substrates such as paints, coatings, stucco, concrete, stone, cementaceous surfaces, wood, caulking, sealants, textiles, leather, wood, preservatives, metal working fluids, drilling muds, clay slurries, glazes, optical brightness, carpet backing, pigments and as a preservative for other aqueous and wet state products, and the like.
