Air caloric test is an essential method to evaluate vestibular system in patients who are suffering from severe external otitis or otitis media with tympanic membrane perforation. To investigate the effects of tympanic membrane perfroration on air caloric test, the author performed the bithermal(cold, 22℃ ; warm, 52℃) air caloric test in 20 healthy normal persons and 30 patients who showed unilateral ear drum perforation. Flow rate and duration of air irrigation were maintained as 10L/min and for 60 seconds in each test, respectively. The results were as follows : 1) In control group, mean latency was 44.7 sec, duration was 111.1 sec, total No. of nystagmus was 119.7, and MSSC was 41.8 deg/sec. 2) UW calculated by latency and MSSC were significantly increased in patients compaired to control. 3) DP calculated by all parameters(latency, duration, TNN, MSSC) showed no difference between control and patients. 4) There were no left-right differences in caloric responses. However, drum perforated side showed short latency and increased MSSC compaired to intact side. 5) No significant inter-individual differences were found in latency and MSSC, but duration and TNN showed significant differences. 6) By cold stimuli, latency was shortened compaired to warm stimuli. 7) In 8 cases, caloric inversion, contralateral beating nystagmus, was observed during warm air irrigation.