Abstract Capillary gas chromatography (GC) is a very useful technique for the determination of complex mixtures of halogenated contaminants. Initially, this technique has shown its merits for the determination of polychlorinated biphenyls and organochlorine pesticides. In addition, it has also broken new grounds towards the identification and quantification of relatively unknown halogenated compounds, often complex mixtures, such as toxaphene, polychlorinated naphthalenes and paraffins and brominated flame retardants. Capillary GC is, however, not the final solution for the determination of all these mixtures. For some of them, with a relatively simple constitution or with only a few major components, such as chlordanes and brominated diphenylethers, a reliable congener-specific analysis may be carried out by single-column capillary GC. For others more advanced techniques will be required. Multi-dimensional (MD) GC techniques, such as heart-cut MDGC or comprehensive MDGC, are still under development or have only been applied for non-routine analyses. Given the importance of some of these complex mixtures, such as several brominated flame retardants, which are still produced and used daily and world-wide, it may be expected that next to the use of GC–MS, these more advanced GC techniques will be used more frequently in the near future. The current state-of-the-art of capillary GC with regard to the different compounds classes indicated below is described. Also, attention is given to the sample preparation. The following groups of contaminants are being discussed: polychlorinated dibenzo- p-dioxins and dibenzofurans, chlorinated bornanes (toxaphene), chlordane, polychlorinated terphenyls, polychlorinated diphenylethers, polychlorinated naphthalenes, polychlorinated alkanes, polybrominated biphenyls and polybrominated diphenylethers.