A flow injection analysis (FIA) procedure is described for the determination of chlorocresol in a parenteral pharmaceutical formulation. The product is directly injected into a carrier stream of water and subsequently reacted with a reagent stream of nitrous acid. The resulting brown nitro-derivative is detrmined spectrophotometrically at 400 nm. The method has been validated and should be spplicable to chlorocresol in other pharmaceutical products and to compounds containg a phenolic ring, assuming abscence of matrix interference.