A twin GC × GC system has been designed which enables the analysis of a sample by means of two different and independent column combinations simultaneously. Both combinations are incorporated in the same oven, using the same temperature programme, and are fed using a 50:50 column-entrance-split. It is demonstrated that, employing combinations of a conventional non-polar × polar and a reversed-type polar × non-polar column set, the information content is as high, and the analytical performance is as good as when using two separate GC × GC systems. That is, there is an appreciable gain of time and a reduction of costs without any loss of quality. The general usefulness of performing, and comparing two mutually different GC × GC runs is further illustrated with FAMEs in olive oil, and pollutants in a sediment sample. © 2004 Elsevier B.V. All rights reserved.