Galapagos Land iguana (Conolophus subcristatus) populations are threatened by introduced species and habitat loss but the intensity of these threats varies between populations. The population sizes across the species range are partially known and suspected to relate to the presence/absence of introduced predators. Although demographic trends are virtually unknown, it is suspected that populations in disturbed areas have a lower recruitment of juveniles and limited population growth. I examined the effects of feral cats on two populations of Galapagos Land Iguana by comparing historical demographic data from cat-absent and cat-present populations. I found cat-present populations exhibited significantly different population structure and morphology to cat-absent populations, including significantly lower juvenile percentage indicating reduced juvenile recruitment as a result of juvenile depredation . Further, I studied a translocated population of land iguanas on North Seymour, and the most undisturbed land iguana population in one of the most active volcanoes worldwide: Fernandina Island. I estimated and compared population sizes to assist the planning of a reintroduction of the species to Santiago Island. I also reviewed and updated the IUCN status of the species and determined that its Vulnerable status is justified, primarily due to its limited geographic range and projected population decline. The results of my research have helped the Directorate of the Galapagos National Park, Island Conservation and Massey University completed the world’s largest translocation of Galapagos Land Iguanas to date: 2139 individuals to Santiago Island.