For the separation and determination of inorganic Cr(VI) and organic Cr(III) in natural water, a sensitive and selective method was developed using a weak basic anion exchange resin micro-column and inductively coupled plasma atomic emission spectrometry (ICP-AES). Under optimized conditions, organic Cr(III) and inorganic Cr( VI) were retained on the column, and eluted with 1. 0 mol x L(-1) HCl and 2. 0 mol x L(-1) NH4 NO3 +0. 5 mol x L(-1) NH3 x H2O respectively. Then the concentrations of Cr(VI) and organic Cr(III) were determined by ICP-AES. The detection limits of organic Cr( III ) and inorganic Cr(VI) were 1. 1 and 1. 4 microg x L(-1) , and relative standard deviations(RSD) were 3. 8% and 5. 6% respectively. The proposed method has been applied to the determination and separation of chromium in several practical water samples with a recovery between 90. 4% and 106. 3%.