The use of clinoptilolites of Western Anatolia in detergents as phosphate substitutes was investigated. The cations present in the clinoptilolite samples were first exchanged with sodium ions. The washing characteristics of detergent mixtures containing surfactants, clinoptilolite, sodium carbonate and sodium sulphate were analysed. The stains of coffee, tea and tomato paste were tested. The washing tests were repeated for different surfactants, i.e. linear alkyl benzene sulphonate, sodium alkyl sulphate and alcohol ethoxylate and for different co-builders, i.e. sodium carbonate and EDTA. In addition, the effects of detergent dose and detergent formulation on washing were investigated. Other factors affecting the degree of soil removal such as shaking time, temperature and water hardness were also studied. The contribution of clinoptilolite to the washability was compared with zeolite A, zeolite X and sodium tripolyphosphate. Increasing the shaking time and temperature improves the degree of cleaning. LAS was the most effective surfactant for use with clinoptilolite. The washing performance of the detergent mixtures used in the present work was found to be 00 comparable with that of commercial detergents at low washing temperatures. Key words: clinoptilolite, detergent builders, phosphate substitutes.