Abstract: It was found that in an ammoniacal buffer medium of pH 9.5,the catalytic effect of bovine hemoglobin on the redox reaction between hydrogen peroxide and acid chrome blue K was inhibited by the presence of isoprenaline,and that linear relationship was kept between values of rate of inhibition and concentration of isoprenaline in the range of 8.1×10-8-1.2×10-5mol·L-1 with its detection limit (3S/N) of 2.2×10-9mol·L-1.On these basis,a sensitive and simple photometric method for determination of isoprenaline was proposed.The proposed method was used for the determination of isoprenaline in its injections and recovery of the method was tested by standard addition method using these samples as matrixes.Values of recovery found were ranged from 92.6% to 105.4% with values of RSD′s (n=5) in the range of 2.6%-5.8%.