A simple, fast, precise and sensitive method for the quantification of IR3535, an insect repellent used in topical formulations, was developed by reversed-phase high performance liquid chromatography. The separation was carried out by using a core-shell silica particles column (Kinetex C18, 5??m, 4.6 mm x 150 mm) with a mobile phase consisting of 0.1% formic acid and methanol (40 : 60 v/v) in an isocratic mode at 0.5 ml/min and UV detection at 220 nm. The calibration curve was linear from 10 to 400 ??M, with regression coefficient r2 = 0.9999. Limit of detection (LOD) and Limit of quantification (LOQ) were found to be 1 and 10 ??M, respectively. Precision and accuracy fulfilled the acceptance criteria. This method was validated and may be routinely used for quantitative analysis of IR3535 from various topical insect repellent liquid formulations.