Abstract: This paper reports a method for simultaneous determination of chlorophyll a and chlorophyll b by synchronous fluorimetry. The scanning wavelength intervals (△λ) of 258nm and 193nm were used and the wavelengths of maximum emission in synchroneous spectra were at 670nm and 654nm for chlorophyll a and chlorophyll b, respectively. This method is simple and rapid, and the ranges of determination were- 0.5-200 ppb. and 0.5-150 ppb, for chlorophyll a and chlorophyll b, respectively. Accuracy of deicrmination was about 5%.