Tran Quyet Thang Cousin problem for monogenic functions with parameter in Clifford analysis Abstract: The Cousin Problem is important in Theory of holomorphic functions in several complex variables. In this paper we study the Additive Cousin Problem for monogenic functions with parameter (is also called semi-monogenic) taking values in a Clifford algebra, which contain solutions of many important systems of partial differential equations in Theoretical Physics. It is shown that this problem is solvable for polydomains. Keywords: Cousin problem, semi-monogenic function. MS classification: 30G35, 32A30, 35J45, 35N05.