New methods for the complete extraction of gibberellins and other hormones from freeze-dried seeds, and for the partial purification and resolution of the extracts on cellulose columns, are described. The presence of gibberellins A4 and A7 in developing apple seeds has been confirmed by thin-layer and gas-liquid chromatography. Bioassay of partially purified extracts in the lettuce hypocotyl test showed that gibberellins first appeared in the seeds about 5 weeks after full bloom, increased to a maximum concentration at 9 weeks and subsequently decreased again, disappearing completely by the time the seed was mature. The rapid build-up of gibberellins was preceded by the appearance of an unidentified hormone, highly active in the Avena mesocotyl assay, which reached its peak concentration 6 weeks after bloom. A second unidentified hormone with similar biological properties reached its highest concentration 13 weeks after bloom, at the time when gibberellins were fast disappearing. It is pointed out that the sequence of hormone production in the apple seed is linked with well-defined stages of embryo and endosperm development and the possible functional significance of the hormones is discussed.