Many conservation projects have weak capacity to monitor their target species and the threats they face, compromising adaptive management. We assessed 74 vertebrate and plant conservation projects worldwide that were supported by the SOS–Save Our Species Programme (now IUCN Save Our Species) during 2012–2015. Our aim was to determine how and where monitoring efforts were focused, identify trends in data availability and make recommendations for improvement. Project managers reported more of a decrease in threats (73%) and improved habitat conditions (68%) than positive population changes (19%), primarily because of the focus of their objectives and limited time to collect population data. More population data were collected on reptiles and amphibians than mammals and birds, contrary to global trends. This probably reflects a greater focus of mammal and bird projects on improving habitats or reducing threats. There were geographical differences in data availability. Lessons learnt that could be applied to future project portfolios include: a common strategic framework should be developed, along with a set of common indicators against which projects can align and demonstrate their contributions; more guidance and capacity building support should be provided to grantees; and a greater allocation of project budgets should be dedicated to monitoring.