Salicylic acid, a phytohormone naturally found in several plants, exerts diverse functions in the plant metabolism, and has been used in medicine and cosmetology.It is usually found in the urine of humans, as the main metabolite of acetylsalicylic acid, a worldwide used drug.Due to the absence of threshold limits in the environment, it is considered as an emerging pollutant.Usual methods for its determination are based on high performance liquid chromatography with mass spectrometry, UV or fluorescence detection.However, these methods require relatively expensive instrumentation and exhaustive procedures for sample clean-up and analyte preconcentration.Aiming to simplify the procedure for salicylic acid determination in waters, and to make the process more environmentally friendly, the aim of this work was the development of an alternative procedure for the determination of salicylic acid in natural waters, exploiting the intrinsic fluorescence of the salicylate ion and the on-column preconcentration in a sequential injection chromatographic system.A linear response between 0.25 and 5.00 μg L -1 and other suitable figures of merit were attained: the coefficient of variation, limit of detection, limit of quantification, and sampling rate were estimated as 3.0% (n = 10), 20 ng L -1 (99.7% confidence level), 60 ng L -1 , and 7 h -1 , respectively.Improved precision and recoveries were obtained in comparison to the LC-ESI-MS/MS reference method.In addition, in view of the low consumption of organic solvent (150 μL of acetonitrile per determination), as well as the absence of sample pretreatment, the proposed method meets the requirements of Green Chemistry.