The intrinsic viscosities of a terpolymer of methyl methacrylate, ethyl acrylate and methacrylic acid, prepared by semicontinuous emulsión polymerization (látex) were measured in acetone and THF at different temperatures. Data were analyzed with the aid of the equations of Huggins, Kraemer, Martín, Schulz-Blaschke and an equation recently suggested by Rao. Relationships between different parameters were also considered The effects of low-molecular weight and water-soluble compounds on the intrinsic viscosities were observed for uncleaned samples of látex as compared to samples purified, by single precipitation or by dissolution and precipitation from THF. Solvent powers and effects of degree of purification and temperature on viscosity are discussed. Polymer-solvents interactions are discussed in terms of the acceptor / donor properties of the solvents.