The globally threatened Wattled Crane (Grus carunculatus) was studied from 2001 to 2004 in the Okavango Delta, Botswana. Between 2001 and 2003, three aerial surveys covering between 8 123 and 10 677km2 were conducted, and the Wattled Crane population estimated to be 1 290 ± 158 based on combined estimates from these surveys. The population estimates were 1 219 ± 343, 1 205 ± 235 and 1 450 ± 273 for 2001, 2002 and 2003, respectively. This shows that the Okavango Delta holds the largest single population of Wattled Cranes in the world, containing over 16% of the global population estimate of <7 700 individuals. The main distribution of Wattled Cranes was the Jao/Boro, Nqoga and Khwai/Muanachira River systems, coinciding with the wettest and most productive parts of the delta. The breeding success, estimated using the proportion of juveniles to adults, was found to be 6.7% during the breeding season of 2003–2004. This estimate is low even though the Okavango Delta is relatively pristine, and is probably an artefact of a stable and large population and a variable environment, coupled with the life-history strategy of the Wattled Crane, a long-lived species.