This study was carried out to investigate the prevalence of Neospora caninum infection in dairy cow and Korean native cattle(KNC), raised in several Chungnam province. To determine the prevalence of antibodies to N caninum, a total of five hundred fifty six sera were analyzed by indirected fluorescent antibody(IFA) test. Five hundred thirty three sera were collected from fifteen dairy herds and twenty three sera were taken from fourteen KNC herds from December 1999 to November 2000. Seropositive ratio of the dairy cattle sera were individually or herdly tested and showed 64.2% and 93.3%, respectively. It was recorded with 78.6% and 47.8% in KNC. The seropositive ratio of dairy cattle was depended on the size of ranch. It was 92.2, 60.7 and 57.9% at the size of less than thirty, thirty to seventy and more than seventy one cattle, respectively However, it was different from the province of Chungnam. The seropositive ratio to N caninum of dairy cattle were 79.5, 53.1, 61.4 and 31.1% at Gongju, Yeongi, Geumsan and Cheongwon, respectively. It showed difference at the growth stage and sex of cattle. The seropositive ratios of N caninum of calf, heifer, premiparous, multiparous(2nd-5th), multiparous (6>th) and bulls confirmed to 25.0, 50.3, 70.3, 71.2, 50.0 and 50.0%, respectively. It was related with brucellosis in cattle. The infected ones with brucellosis were 75.7% of seropositive ratios to N caninum. The results of this study indicated that N caninum infection was widespread in Chungnam province and confirmed existing with brucellosis in cattle.