The present study was carried out to investigate the prevalence of Neospora caninum infection in Korean indigenous cattle and calves of abnormal deliveries and focus on correlation between malformation and N caninum infection. To determine the prevalence of antibodies to N caninum, sera of 473 Korean indigenous cattle from slaughter house were tested for N caninum antibodies using indirect fluorescence assay. Of the 473 cattle sera, 9.5% (45/473) showed positive against N caninum. Regional seropositive rates of the samples were 16.7% (5/85), 11.0% (11/100), 8.8% (21/240) and 5.9% (5/85) at Kyonggi, Gyeongbuk, Daegu and Kyongnam province, respectively. In female, seropositive rates were 17.5% (25/143) and 6.1% (20/330) in male. During the period from march 2000 to August 2001, 55 abnormal deliveries of Korean indigenous cattle including abortion, stillbirth and congenital malformation were examined by histopathological, immunohistochemical and serological methods for evidence of N caninum infection. Of the 55 abnormal deliveries, only 5 calves showed positive reaction against N caninum in serological test. In microscopical observation, gliosis and nonsuppurative myositis were observed. However, Neospora-like organisms were not detected by either periodic acid-schiff (PAS) reaction or immunohistochemical technique. Taken together all these data, this study indicate that N caninum infection was widespread in breeding farms of Korean native cattle, but correlation between malformation and N caninum infection was not recognized.