Seeds and leaves of Vicia faba L. contain considerable amounts of 4-Cl-indoleacetic acid as determined by gas-liquid chromatography and gas-liquid chromatography-mass spectrometry. The unchlorinated auxin could not be detected in either leaves or seeds at different stages of development. The developmental stages of fruits and seeds were characterized by the rate of straight growth of pods, the rate of fresh weight increase, and the development of the endosperm. The peak of 4-Cl-indoleacetic acid content per seed coincides with the maximum rate of water accumulation in the seeds.