Abstract. On the inter-domain Internet today, the address prefix origin in our BGP operations has become a major security concern. This critical problem can be stated simply as “Is the originating Autonomous System (AS) authorized to advertise the destination address prefix?” In the long term maybe we will be able to prevent this problem by applying proposed solutions such as SBGP[1] or SoBGP[2]. However, in practical network operations, it is critical to monitor and analyze all the BGP events potentially related to this BGP origin problem. In this paper, we have analyzed OASC (Origin Autonomous System Change) events, generated from the Oregon Route Views [4] archive, related to the Brazil BGP network. Our main focus is on how the Brazil BGP operation has been interacting with the rest of the Internet in the past five years. Also, we provide some possible explanations for OASC anomalies in Brazil.