This chapter examines the key aspects of verification and the role small states may play in three fields of arms control, and aims to compare the results. These are: conventional arms, comprehensive test ban, and chemical weapons. The independent variables include: general political conditions; technical conditions; political conditions for smaller states; technical conditions for smaller states; and political and technical conditions for a multilateral verification body. The dependent variables include objective opportunities for and obstacles to smaller states' participation in each area of arms control and, on the other hand, subjective possibilities for their involvement. The political conditions are the prerequisite for achieving a verifiable agreement. Arms control agreements without sufficient technical means to verify them are meaningless. In order to be accepted as third parties, smaller states have to be accepted by the alliances to conduct verification. "Constraints" in the field of conventional arms control might offer verification possibilities for smaller states to make a contribution.