Radioactive gibberellin A5 (3H-GA5) was synthesized from gibberellic acid. When it was applied to dwarf peas grown in the dark, an average of 3% was converted to another acid gibberellin within 48 hours. The biological activity of the metabolite did not account for the response to applied GA5. GA5 is therefore assumed to be biologically active per se.3H-GA5 did not appear to form a stable complex with a macromolecule in pea shoots. When injected into dwarf pea pods, 3H-GA5 was readily metabolized by maturing seed to more water-soluble substances and to two other acidic compounds. This metabolism continued even throughout germination of the seed without reconversion of the metabolites to GA5. It is concluded that “bound” GA5 plays no part in the germination of dwarf pea seeds.