The symbiotic trade relations between Nigeria and the Republic of Benin is an ever current subject with few studies focusing on the shadow substance, nature and actors involved in the process. This paper will attempt to offer insight into the dynamics of the shadow trade, the actors and the motor-force. It will review the cabotage laws of the two countries and how they aid or fuel the shadow trade. Also, it will examine the volume of the trade by a probe of its uncaptured dimension and its implication for the size of the Nigerian economy. Besides, the paper will account for bilateral trade relations. It will argue, drawing abundantly from interviews, documentary evidence and secondary literature that: One, a huge volume of uncaptured trade takes place between the two countries. Two, there is a tacit official sanction of the trade by the Nigerian government on grounds of African solidarity despite its deleterious effect on government revenue especially from import tariff. Three, the trade indicates that the current size of the Nigerian economy is more than its valuation. The paper will conclude that while it is difficult to completely eliminate shadow exchange, it can be minimised by formalising the illicit channels and unbundling of official and physical constraints through the joint efforts of both countries.