During continuous casting of slabs a cast structure consisting of dentrites and solidified residual melt is formed with a macrosegregation (centre segregation) developing in the centre of the slab. Centre segragation is a quality feature of slabs and it also has an effect on the proces- sing and quality of the final product. Due to increasing requirements for the physico-chemical characteristics of steel products, it is essential to be able to measure and to evaluate centre segragations before one can start minimising the level of segregation. A new valuation method called ATLAS (Automatic Line Scans for Analysis of Segregation) is being developed for an efficient evaluation of centre segregation. ATLAS is based on OES-PDA (Optical Emission Spectrometry–Pulse Discrimination Analysis), which is an analysing method with automatic sample manipulation as well as a specific evaluation algorithm for determining meaningful segregation factors. The aim of this thesis is the characterisation of centre segregation of sourgas resistant slabs both lengthwise and widthwise. For this reason, it is necessary to introduce an analysis of the valuation method ATLAS by using selected parameters (repeated measurements, MnS-inclusion, range and mode of measurement) and to know the validity of segregation factors. The analysis shows that valid and reproducible segregation factors can be determined by using a specific approach and setting of parameters. In addition, these factors tend to provide similar results when compared to micro-sample analyses. The characterisation of centre segregation by means of ATLAS is possible and shows significant variations of the production-relevant segregation factors in sourgas resistant slabs. Nevertheless, these variations are below the limit value, which is relevant for the quality of the final product.