Colophony is known to cause occupational asthma and dermatitis. Biological monitoring may be useful in assessing exposure. This paper describes a method for the analysis of dehydroabietic acid in urine and its potential use as a marker of colophony exposure. The method involves hydrolysis, solvent extraction, derivatization and analysis by gas chromatography-mass spectrometry. Twenty-eight workers from a soldering factory in South Africa were monitored. Results showed that levels of dehydroabietic acid in urine may be correlated with a subjective assessment of exposure.