A simultaneous determination of micro amounts of albumin and globulin fractions by fluorometry with only reagent alpha,beta,gamma,delta-tetra(4'-carboxyphenyl)porphin (TCPP) in the aqueous solution has been developed. Under the experimental conditions (5.6 x 10(-7) mol/liter of TCPP, pH 3.0, and at room temperature), the linear range of this assay was 0.09-12 mu g/ml and the detection limits (3 S/N) were 60 ng/ml for albumin and 90 ng/ml for globulin, respectively. The human serum samples were measured satisfactorily by using this method. (C) 1996 Academic Press, Inc.