A rapid, cheap and environmentally friendly DES-based LPME method for the determination of Ponceau 4R dye in real samples by UV-Vis spectrophotometry has been developed. Tetra-n-butylammonium bromide (TBAB) and decanoic acid (DA) were two components of DES solution used in the presented work. TBAB and DA were used to get DES. pH, DES type and volume, THF volume, ultrasonication and centrifuge time, sample volume and interfering effects, which are effective on the yield of the method, have been optimized. Ponceau 4R dye was extracted to the DES phase at pH 3.0. Limit of detection (LOD), limit of quantification (LOQ) and preconcentration factor were found as 5.97 mu g/L, 18.1 mu g/L and 40, respectively. The validation of the developed method was determined by addition recovery studies to water and cosmetic samples.