A rapid, accurate and sensitive method for the determination of salbutamol in plasma and urine is described. Salbutamol is extracted using solid-phase techniques and converted to an indoaniline dye by reaction with dimethyl-p-phenylenediamine. The indoaniline is separated using high-performance thin-layer chromatography and quantified by absorption microdensitometry at 650 nm. The method is sensitive down to 20 ng/ml in urine and to 1 ng/ml in plasma and provides data in good agreement with that obtained by gas chromatography--mass spectrometry. The method can be used for analysis of pharmacokinetic studies.