Neurotological follow-up observations were conducted on 38 of 43 cases of vestibular neuronitis treated between 1972 and 1983. The average observation period was 1 year and 3 months (range from 1 month to 9 years and 4 months) and 17 cases were followed for more than 1 year. The tests used for evaluation in this series were the following: spontaneous nystagmus, head positional nystagmus, a caloric test and a computed galvanic body sway test (GBST) conducted by Yamaguchi University. Changes in subjective symptoms are also noted. The main subjective complaint was vertigo (whirling; 93%). The remaining subjects noticed a floating sensation and unsteadiness of gait. In 50% of the cases, vertigo subsided by the end of the 3-month period, but 6 subjects suffered from an intractable dizzy sensation for over 1 year. Even after 3 years, 3 of these 6 cases were bothered by dizzy sensations. Especially in the central lesion, these 3 subjects had no other causative disease. Spontaneous nystagmus, which was usually horizontal and direction fixed, remained in 50% of the cases after the 1-year period. All of the cases tested showed reduced caloric responses. 21 of the 38 cases showed no response in cold caloric stimulation (including ice water) at the initial test. 13 of the 21 cases were followed satisfactorily and examined twice or more by caloric testing. 5 of these 13 cases did not recover in the caloric test even after more than 1 year.(ABSTRACT TRUNCATED AT 250 WORDS)