A novel method of separation that uses water as a stationary phase in capillary gas chromatography (GC)is presented. Through applying a water phase to the interior walls of a stainless steel capillary, goodseparations were obtained for a large variety of analytes in this format. It was found that carrier gashumidification and backpressure were key factors in promoting stable operation over time at varioustemperatures. For example, with these measures in place, the retention time of an acetone test analytewas found to reduce by only 44 s after 100 min of operation at a column temperature of 100◦C. In termsof efficiency, under optimum conditions the method produced about 20,000 plates for an acetone testanalyte on a 250 m i.d. × 30 m column. Overall, retention on the stationary phase generally increasedwith analyte water solubility and polarity, but was relatively little correlated with analyte volatility.Conversely, non-polar analytes were essentially unretained in the system. These features were appliedto the direct analysis of different polar analytes in both aqueous and organic samples. Results suggestthat this approach could provide an interesting alternative tool in capillary GC separations