To elucidate the profiles of plant hormones involved in growth and ripening of grape fruit at various stages, grape bunches of Campbell Early grape bunches (Vitis labrusca ‘Bailey’) which were harvested from 14 to 63 days after full bloom (DAFB) were divided into skin, pulp and seeds. Endogenous plant hormones, which included indole-3-acetic acid (IAA), abscisic acid (ABA), trans-zeatin (Z), isopentenyl adenine (iP), jasmonic acid (JA), methyl jasmonate (MeJA), gibberellin₁ (GA₁), and gibberellin₄ (GA₄), were quantified by liquid chromatography-mass spectrometry (LC-MS). Throughout the sampling period, higher IAA concentrations were maintained in the seeds than those in the skin and pulp. In the seeds, the Z concentration was highest at 14 DAFB and then decreased rapidly. However, in the skin and pulp, the iP concentration increased over the course of sampling. The ABA concentration in the pulp was high around veraison. The JA concentration in the skin reached 4,100 pmol·g⁻¹FW at 27 DAFB. The MeJA concentration in the skin also increased rapidly. These results suggest that increases in iP concentration in the skin and pulp are involved in maturation.