This article reports on a study of surface phenomena in the interaction of jet fuels with water. It attempts to improve the accuracy of quantitative ratings of surfactant contents in jet fuels. The presence of surfactants in fuel can be judged from the results of fuel interaction with distilled water (GOST 16564-71) or a phosphate buffer solution consisting of 1.15 g K/sub 2/HPO/sub 4/ and 0.47 g KH/sub 2/PO/sub 4/ in 100 ml of water (ASTM D 1094-72). These methods do not take into account any changes in condition of the meniscus after mixing the test fuel with the aqueous phase and subsequent 5-min standing, nor do they take into account the presence of drops on the cylinder surface. It is recommended that in evaluating the condition of the meniscus, the changes in its height after mixing and 5-min standing should be recorded. The presence of drops on the cylinder wall and the transparency of the liquid phases should be rated after standing for 30 min.