A retiabte and sensitive method is developed for the detection of β-blockerswhich are excreted in free or conjugated forms in human urine.9 β-blockers werederivatized by MSTFA and MBTFA and subjected to GC/MSB analysis.Both chromato-grams and mass spectrometric data were obtained from full scanning mode.This methodis suitable for routine screening and confirmation of β-blockers in doping control.