Tympanometry was used to follow the maturation of middle‐ear function in neonatal chicks from hatching to 10 days of age. The methods have been described elsewhere [Relkin and Saunders. J. Acoust. Soc. Am.63, Suppl. 1, S42 (1978)]. Subjects in each of five age groups were anesthetized, mounted in a head holder, and the tympanic ring was surgically exposed. A small hole was made in the contralateral tympanic membrane in order to equalize middle‐ear pressure to ambient pressure through the interaural pathways. A tympanometer probe was sealed directly over the tympanic membrane using a short piece of metal tubing to couple the probe to the tympanic ring. The magnitude of the volume velocity required to reach a criterion value of sound pressure was measured at frequencies between 0.4 and 1.8 kHz. Acoustic admittance at the tympanic membrane was calculated from the volume velocities measured when the tympanic membrane was stressed with a pressure of +200 mm H20 and when it was at ambient pressure. In all groups a monotonic increase in admittance magnitude was noted with increasing frequency. Phase, for low frequencies, was about 90° and decreased toward zero as the test frequency increased. There was relatively little change in admittance magnitude over the range of ages tested. These data further reflect the high degree of auditory development in the newly hatched chick.