To date no studies have been undertaken on the costs and benefits of IAS management in the Caribbean. This may partly explain why there has been negligible funding to combat the onslaught of these exotic species in the region. As a result it was decided to provide individuals involved in the UNEP-GEF Project, "Mitigating the Threats of Invasive Alien Species in the Insular Caribbean" with training and an opportunity to undertake Cost-Benefit Analyses (CBAs) on some selected IAS. The CBAs undertaken and reported in this publication clearly demonstrates that the benefits of managing IAS outweigh the costs.