A cross-sectional epidemiological study was carried out ftom September 2004 to March 2005rnto detemline the scroprevalence of bovine brucellosis in the intensive and extensive cattlernproduction systems of Tigray Region, to identify the risk factors that contribute to thernoccurrence of brucellosis and assess the public health significance of the disease.rnThe study populations were compnised of indigenous and crossbred cattle in the Region andrnsamples were selected by two-stage cluster sampling . Serum samples collected from 1,951rncattle above six months of age, of which 1.135 from the intensive farms and 816 from thernextensively managed herds were screened for Brucella antibodies by the Rose Bengal PlaternTest (REPT) and the reactor sera were further tested by the Complement Fixation Test (CFT).rnMoreover, information was gathered on age. sex . herd size. managemenl. and agro-ecology ofrneach sampled animal to determine the risk factors for brucellosis seropositivity. Likewise.rndata on farm or herd-leveI risk factors and other farm characteristics were obtained using arnquestionnaire survey. which was administered in person to 112 intensive farms and membersrnof animal owners in the 26 extensive herds. Furthermore. in order tornassesrnsrnthe zoonoticrnimporlance of the disease. 185 human serum samples were also screened for brucellosis.rnIn this study. thernoverallrnseroprcvalence of Brucella antibodies in cattle was 1.49% Howeverrnindividual animal seroprevalence was found to vary from 0. 26% in the intenSrnsive farms tornrnrn3.19% in animals reared under the extensive management system statisticall significantrndifference was observed in seroprevalence values between the intensive and extensivernmanagementrnsystemsrn(p0.05). Significant increment ofrnseropositivity was also observed as herd size increases from small to medium (p