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Organotin compounds (OTC), mainly tributyltin (TBT), have been used since the 1970s as biocides in the composition of antifouling paints. Due to its physical-chemical characteristics, TBT has high toxicity to the marine environment affecting non-target organisms. The present study aims to develop a method of direct visual identification of TBT in antifouling paints using the cyclopalladate complex, 4- (2-thiazolylazo) resorcinol (TAR-Pd), synthesized in our laboratory. Tests were performed in blank and in the paint matrix with the following OTC: TBT-O; TBT-Cl; TPT-Cl; DBT-Cl (tributyltin oxide, tributyltin chloride, triphenyltin chloride, dibutyltin chloride), in addition to the SnCl 4 and SnCl 2 compounds (tin IV chloride and tin II chloride), all at a concentration of approximately 20 g/ kg of dry paint). The test was performed by applying paint samples to test bodies and scraping a few tens of milligrams of the dry paint film. The scraped paint samples were submitted to the test, showing a different staining reaction for the TBT-Cl and SnCl 4 samples concerning blank and other samples (TBT-O, TPT, DBT-Cl, and SnCl 2 ). Solution tests were performed to characterize reaction products by spectroscopy in the visible band. The method developed has potential for application in real samples, being selective for TBT-Cl and SnCl 4 in an acid medium, obtaining a limit of detection, in the range of 1-10 mg/kg dry paint., (© 2024. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)