The automated turbidimetric method presented allows a fast and accurate quantitation of plasma proteins. The analysis requires somewhat more antiserum than the radial immunodiffusion and the electroimmunoassay. However, this is compensated for by more rapid results and lower labour cost. The reference values for albumin, haptoglobin and IgG are the same as obtained by other immunological methods. The correlations with radial immunodiffusion and electroimmunoassay are good within the normal range. At high monoclonal IgG concentrations this method is better correlated to dye binding properties (scanning of electropherograms) than is the electroimmunoassay.