Abstract: Charge transfer reaction with purpurin was applied to the spectrosphotometric determination of azithromycin. In ethanol medium,azithromycin reacted with purpurin to form charge transfer complex,which exhibit a strong absorption maximum at 546 nm. Under the optimum condition,the linear relationship between values of the absorbance and the mass concentration of azithromycin was found in the range of 8.0-120 mg·L-1 with detection limit (3s/k) of 2.6 mg·L-1. The method was applied for the analysis of azithromycin tablets obtained from market,giving results in agreement with the labelled value. Values of recovery found by standard addition method were in the range of 98.8%-101%,with RSD′s (n=5) in the range of 1.7%-2.4%.