Based on gaseous compound introduction as pyrrolidinecarbodithioate chelates of Cr, Co, Mn and Ni by electrothermal vaporization (ETV) in inductively coupled plasma optical emission spectrometry (ICP-OES), a novel method for the determination of trace Cr, Co, Mn and Ni was developed. It was found that in the presence of ammonium pyrrolidinecarbodithioate (APDC) the trace amounts of analytes were vaporized at a low temperature of 1500 degrees C. The main factors affecting the formation and vaporization of analytes chelates were investigated in detail. Thermal gravimetric analysis of Cr-APDC, Co-APDC, Mn-APDC and Ni-APDC chelates and UV-vis analysis of the sample vapor collected in CHCl(3) after vaporization of their chelates indicated that the analytes were vaporized and transported into ICP as their chelates. Under the optimized conditions, the limits of detection (LOD) (3sigma) and the relative standard deviations (R.S.D.) of Cr, Co, Mn and Ni were 0.36, 0.19, 0.073 and 0.32 ng, and 3.9, 4.9, 3.8 and 3.3% (c=0.5mugml(-1), n=7), respectively. By combination with a solvent extraction step, the proposed method had been successfully applied to analysis of Cr, Co, Mn and Ni in the artificial seawater. To evaluate the accuracy of the developed method, two certified reference materials (human hair GBW 09101 and poplar leaves GBW 07604) were also analyzed, and the determined values obtained were in good agreement with the certified values.