An in-syringe ionic liquid-based single step microextraction has been analytically presented. 1-butyl-3-methylimidazolium hexafluorophosphate as extractant and Triton X-100 as dispersing medium were used. Cd-Dithizone was extracted within a syringe. The effects of some variables such as [C(4)mim][PF6] volume, pH, TX-100 volume, dithizone concentration, incubation time, diluents nature and matrix effect were investigated. The limit of detection and preconcentration factor were found as 0.35 mu g L-1 and 50, respectively. The validity was checked by using certified reference materials. The relative standard deviation (RSD) was 4.2%. The method was satisfactorily applied to preconcentration of cadmium in natural water samples. (C) 2015 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.