Confidence-building measures (CBMs) are an assortment of activities that states engage in to become more sure that each understands the true actions and/or intentions of the others. An individual CBM is usually centered on a specific military or security issue. CBM’s are one way to create the groundwork for increased confidence regarding treaty compliance. In regard to the BWC, CBMs could concentrate on the types of agents possessed and/or the quantities of agents possessed. CBMs could provide an opportunity to reveal justification for all types and quantities of agents to the international community. CBMs can be voluntary, legally binding, or politically binding. The tendency of many countries to neglect the obligations of politically binding CBMs has eroded optimism regarding the value of CBMs. Without random checks on the accuracy of information, states have little incentive to complete what may be burdensome reporting requirements. A compliance protocol with strong complementary measures that reinforce the goals of deterring the acquisition and use of biological weapons is a necessary foundation. Such a protocol is the only way to provide constant professional attention to biological activities in BWC member states. Building confidence in compliance is generally limited to those countries that are in a middle ground on a scale of confidence. One CBM to be considered for the BWC is that surveillance of publications should not be an obligation of states, but of the BWC organization staff. Another is that surveillance of legislation should be a legally binding obligation of states. Confidence-building visits are inferior to legally binding non-challenge visits. Multilateral information sharing and exchange visits should be encouraged to show states’ willingness to comply with their obligations, not because these measures are likely to yield much confidence in compliance.