Sample pretreatment is often the bottleneck of a tracelevel analytical procedure. In order to increase performance, increasing attention is therefore being devoted to combining sample pretreatment on-line with the separation technique that has to be used. In the present review, a variety of procedures in use today for sample treatment coupled on-line to capillary gas chromatography (GC) is briefly discussed. Special attention is devoted to coupled-column techniques such as SPE-GC and LC-GC (SPE, solid-phase extraction; LC, column liquid chromatography) which are topics of much current interest, also because of their frequent use in so-called hyphenated systems.