The border between Cameroon and Nigeria is also the border between West and Central Africa and the two regional trade communities of ECOWAS and CEMAC. Despite political tensions between Nigeria and Cameroon in the past, there is significant potential to trade between the two economic blocs. Although official trade statistics indicate that existing flows are small, we find that trade flows are under-reported by up to a factor of 50, and that actual trade flows are a multiple of what official data suggest. Similar underreporting might also take place along other land borders in the region. This note outlines the critical barriers that constrain trade between Nigeria and Cameroon, describes the practical norms that have emerged as a response to those constraints, and recommends key reforms for the governments to undertake.