Analysis of the low levels of catecholamines and metabolites in tissue and biological fluids has necessitated the use of highly sensitive analytical techniques. Earlier procedures utilizing radioenzymatic and immunological assays, gas chromatography or fluorimetry have generally been superseded by highly sensitive and selective chromatographic methods utilizing electrochemical or fluorimetric detection. The development of high-performance liquid chromatography (HPLC) methods for the measurement of plasma metadrenalines and the combination of HPLC with tandem mass spectrometry provides additional procedures with minimum interference from drugs and drug metabolites. This review summarizes the methodology currently available for the measurement of catecholamines and metabolites in plasma and urine, the influence of sample collection protocols and the clinical application of the methods for the biochemical detection of catecholamine-secreting tumours.