The combination of the high resolving power of capillary columns and the extreme sensitivity of the electron capture detector gives us a powerful tool for the analysis of chlorinated pesticides. The connection of capillary columns to gas chromatographic equipment not speically designed for these, requires special adaptations. A generally suitable connection for capillary columns to injection ports and to the Hewlett Packard electron capture detector is described. The preparation of capillary columns suitable for pesticide analyses is discussed. Results obtained with synthetic mixtures and with biological samples are given. The equipment as described, proved to be suitable and reliable for the analysis of chlorinated pesticides.