The fact that the polyanionic long chains of mucopolysaccharides (MPS) can be precipitated with detergents such as cetylpiridiniumchloride (CPC) has been used in the development of a method for the quantitative estimation of total MPS in urine. Urine samples are all brought to an osmolarity of 300, after which an equal volume of 0,1% CPC is added to each sample. The turbidity is determined spectrophotometrically after 5 minutes. Chondroitin sulphate A was used as an internal standard. Normal values obtained for different age groups in the population of Pretoria are discussed.