Physical loading can be monitored by measurement of the amounts of urinary protein. The Bio-Rad method in combination with gelfiltration gave the following results. 1. The presence of albumin and γ-globulin in proteinuria was recognized by immuno-diffusion in antigen-containing gel. The presence of α(1)-Acid-Glycoprotein, Transferrin and Zn-α(2)-Glyco-protein was also demonstrated. However, other proteins need to be confirmed. 2. With the direct Bio-Rad method, some low molecular substances other than protein showed coloration. Urinary protein over 4000 molecular weight could be measured by removing lower molecular weight substances by gelfiltration. (Fil-Col method). 3. Small amounts of urinary protein could be determined by the modified turbidimetric method of Meuleman. Good correlation was obtained between the Fil-Col method and the turbidimetric method, and between the Fil-Col method and the TONEIN-TP method. 4. From the above results, it was concluded that the Fil-Col method is useful for the exact quantitative determination of minute amounts of urinary protein, and that the TONEIN-TP method is useful for screening of minute amounts of urinary protein.