Abstract: In a B-R buffer solution of pH 11.2, an association complex between acridine orange and yeast ribonucleic acid was formed, leading to enhancement of intensity of resonance scattering of the reaction system. The magnitude of increase in resonance rayleigh scattering intensity (ΔI) was found to keep linear relationship with the mass concentration of yeast ribonucleic acid in the range of 0.05-15.0 mg·L-1 when measured at 333 nm (the wavelength of maximum scattering of the reaction system). Detection limit (3s/k) of the method was found to be 0.017 mg·L-1. Based on these facts, a simple and rapid method for determination of yeast ribonucleic acid was proposed. Recovery was tested by addition of standard solution to 2 blank simulated samples, value of average recovery found was 99.0 % with average RSD (n=5) of 1.3%.