The findings of a study on reproductive disorders and their causes with 685 dairty cows raised on dairy farms located in Cheju city, Jochun, Hallim and Sung-up are summarized as follows; 1. Among a total 685 dairy cows, 149 heads were identified as having reproductive disorders. They were subdivided into 26 genital organ diseases (3.8%), 53 delivery abnormalities (7.7%), 17 stagnation of after-birth (2.5%), 23 long period nonestrus (3.4%) and 30 repeat breeders (4.4%). Also, the regional incidence of those disorders was recorded as high as 30.8-31.5% in Jochun and Cheju city, and as low as 12.6-16.6% in Sung-up and Hallim districts. 2. The regional incidence of delivery abnormalities was estimated as high as 10.7% in the Cheju city area, and gradually reduced to 8.8% in Jochun, 6.8% in Sung-up and 6.2% in the Hallim district. Abortion (3.1%), stillbirth (2.0%) and 욘새챰 (2.6%) were included in the delivery abnormalities.