This study was carried out to determine the seroprevalence of bovine leptospirosis in Kayseri, Turkey and to detect the leptospires in blood and urine of clinically suspect animals by serologic and molecular methods. A total of 2395. blood samples were collected from slaughterhouses located during 12 months (from May 2005 to April 2006) determine the seroprevalence. In addition, blood and urine samples were collected from 500 clinically leptospirosis suspect cattle. Microscopic Agglutination Test (MAT) and Enzyme Linked Immunosorbent Assay (ELISA) were used as serological tests. Polymerase Chain Reaction (PCR) was used for molecular examinations. In the serological analysis of 2395 blood samples collected from slaughterhouses, 609 (25.42%) and 433 (18.07%) samples were found to be positive by the MAT and ELISA, respectively. Seven (1.40%) out of 500 leptospirosis suspect cattle were found to be infected by the MAT and ELISA and Leptospira interrogans serovar Hardjo and L. kirchneri serovar Grippotyphosa were the predominant serovars. And also leptospires were detected in the urine samples of these 7 cattle (1.40%) by PCR. No agent was detected in the blood of suspect animals by PCR. The results of this study have shown that leptospirosis is highly prevalent and predominantly caused by L. interrogans serovar Hardjo and L. kirchneri serovar Grippotyphosa in this region. Because PCR can compete to the serological tests for detecting the leptospires in urine samples of suspect animals, the molecular analysis may contribute to the diagnosis of the infection.