This study was carried out to investigate the status of reproductions and the occurrence of alternate year calving cows. 615 Cheju native and cross-bred cows and heifers fed in 5 villages were surveied, and the result abtained were as follows: 1. Average age at first calving in the regional groups varied by two months when average out was 38.2 and 40.5 months in the early and late by regions, respectively. 2. There was an average of 90.4 days from calving to first estrus excluding alternative year calving cows. However it had an average of 174.3 days from calving to first estrus in all cows investigated. And there were high significant differences among the villages (p. $lt;0.01). 3. The alternative year calving percentage averaged from 13% to 23% in regional groups and was 9.5% in 1980, 33.5% in 1981 and 11.9% in 1982 (p $lt;0.01).