We identified the synthetic cannabinoid JWH-203 [1-pentyl-3-(2'-chlorophenylacetyl) indole] by coordination of various spectroscopic analytical procedures; the data that we obtained may be useful for confirming the presence of this phenylacetylindole in illegally distributed products. In previous studies, several molecules that were identified as synthetic cannabinoids were found in different products advertised as herbal mixtures; the identification of new psychotropic molecules surreptitiously included in products allows them to be added to the official list of psychotropic substances possessing cannabimimetic activity. We used liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry techniques to determine basic information about the structure of JWH-203; our data were corroborated by the results of liquid chromatography-ultraviolet spectroscopy and confirmed by nuclear magnetic resonance analysis and high-resolution accurate mass detection.