Among the several ways of speeding up chromatographic separations, (negative) thermal gradient GC (TGGC) has evolved as a useful technique with great potential for fast and highly efficient separations. The main idea is to use an experimental set-up where the sample is injected at the hot end of a short (2-5 m) capillary GC column and travels towards the detector at the cold end of the column. This leads to a thermal focusing effect as the peaks move along the column, enabling narrow peak widths and consequently high column efficiency. We report here our individual realization of TGGC which is based on a cylindrical ABS housing that has a spiral grove along its hull and is filled with a polymer foam material. The GC column is inserted in a directly resistively heated stainless steel capillary that is positioned just above the spiral grove of the cylinder. While the capillary is uniformly heated by direct current passage, it is non-uniformly cooled by an air stream that is passed through the foam filling of the cylinder, leading to a stronger cooling at the bottom end and at a reduced cooling at the top end of the cylinder. A negative thermal gradient is thus realized along the column as a consequence of the different heating and cooling rates. We will describe here the different design considerations, leading to a TGGC instrument, and how they affect chromatographic performance. The feasibility of this set-up is demonstrated in the separation of real-world samples. Limitations of this TGGC set-up are discussed and ways to overcome these proposed. Acknowledgment: The authors gratefully acknowledge the funding of this work by the Austrian Research Promotion Agency (FFG), Proj. no. 879613 (“OPERION”).