Thin-layer chromatography, gas-liquid chromatography, and mass spectrometry were used to identify gibberellins isolated from mature seeds of both Cucumis sativus (cucumber) and Cucumis melo (muskmelon). The gibberellins were extracted and purified by organic solvent fractionation, paper and thin-layer chromatography, and crystallization. Seeds of C. sativus were found to contain gibberellins A1, A3, A4, and A7 with A1 the predominant species. Seeds of C. melo contained gibberellins A1 and A3 and a trace of A5. Direct probe mass spectrometry of the gibberellins proved successful for identification purposes. Distinctive molecular ions and fragmentation patterns were obtained for each gibberellin.