An assay procedure is described to quantitate low picogram concentrations of catecholamines in human plasma using reversed phase ion-pair HPLC with electrochemical detection. Optimization of chromatographic conditions allows use of samples as small as 0.25 mL. The overall recovery of 78% offers high precision and accuracy at low concentrations. The lower limit of detection is 0.87 pg/mL for epinephrine, 3.5 pg/mL for norepinephrine and 8.3 pg/mL for dopamine.