The analysis of gibberellin GA3 by high performance liquid chromatography (HPLC) was carried out with mu Bondapak C18 column. The developed reversed phase HPLC procedure enables the separation of different GAs with high resolution by means of ionic suppression, including the separation of double bond isomers GA1 and GA3. This method is convenient (without the necessity of derivatization), rapid (15 min for one overall run), sensitive (0.5 microgram is sufficient for precise assay), and has fine linearity (r = 0.999, n = 5) and reproducibility (relative standard deviation < 2%, n = 4).