This aim of this paper was to provide empirical evidence of market integration in the beef cattle industry of the MERCOSUR economic bloc. This region possesses the largest commerical bovine herd in the world and explains one quarter of the international trade for beef. The study included size relevant cattle markets located in the four original members of the bloc. The analysis was conducted using a fractional cointegration approach proposed Marinucci and Robinson (2001). The fractional integration parameters and the error term of the cointegration equations were computer using a semi-parametric approach developed by Geweke and Porter-Hudak (1983). The null hypothesis of 'separate markets' could not be rejected even when the general bahavior of the series under analysis encouraged the idea of some market integration. Despite the common trends, their response to specific shocks was dissimilar and, most importantly, the reversion of the disturbed series to equilibrium was always slow.