Behavior of chromous and chromic ions in the atomie absorption spectroscopy was investigated in neutral aqueous solutions and various acid solutions in the presence, and absence, of sodium sulfate, using air-hydrogen and air-acetylene flames. In 0.1-1 N sulfuric acid solution containing 60-4000 ppm sodium sulfate, both chromium ion exhibited the same and constant sensibility and the maximum sensibility was obtained under the conditions as shown below ; Flow rate : air 8.0 liter/min, acetylene 2.8 liter/min and burner height : 5 mm. These results were applied to determination of chromium in food coal-tar dyes and a simple and rapid method for analysis were established.