A procedure using SPE for the quantitative determination of oil films and slicks floating on water surfaces was developed. During phase one of the study, nine oil loadings (Exxon #6 fuel oil: 3-38 mg/sq cm) were sub sampled with C18-SPE disks in replicates from the surface of 1 L beakers. A modified SPE method using C-18 SPE disks allowed for quantitative recoveries of oil from surface slicks/films. The sampling efficiency was strongly linear over the whole range tested, the variability was < 10%, and the oil was collected by the SPE disks in a 1:1 ratio relative to the water surface loadings. The application of this method to a meso-scale salt-water wave tank showed a strong potential for this technique to be used for the quantification and fingerprinting of oil present in meso-scale to large-scale slicks/films in experimental or natural settings. This is an abstract of a paper presented at the 23rd Arctic and Marine Oil Spill Program, AMOP Technical Seminar (Vancouver, British Columbia, Canada 6/14-16/2000).