Streptavidin (6.25 μg/ml, sigma)diluted in distilled water was coated for 3 h (100 μl/well) at room temperature to microtiter strips. Anti-digoxin antibody was modified by biotin. The assay with these strips was used for the measurement of digoxin. It provideds a sensitivity of 0.0964μg/L. The assay has an intra-assay coefficient of variation of 8.9% (at 0.5012 μg/L), 5.9% (at 1.5631 μg/L), 2.4% (at 3.9678 μg/L). The inter-assay coefficient of variation is 15.8% (at 0.8722 μg/L), 10.1% (at 1.1867 μg/L), 9.2% (at 3.1726 μg/L). In spiking experiments with serum samples, the mean recovery of added digoxin is 97.45% (range 89.07%～107.22%). The assay was compared with FPIA. A linear regression analysis yielded a slope of 0.9640, an intercept of 0.1564 and a correlation coefficient of 0.9488.