Data were collected on species killed by lions Panthera leo in Hwange National Park, Zimbabwe between 1998 and 2004. Lions killed predominantly large to medium-sized herbivores, concentrating on buffalo Syncerus caffer, elephant Loxodonta africana, giraffe Giraffa camelopardalis, wildebeest Connochaetes taurinus and zebra Equus burchelli. These species made up 83% of all lion kills found and 94% of the biomass of kills actually observed. Elephant calves made up an unusually large proportion of lion prey during the study period (23% of kills recorded). All elephants killed were dependent juveniles. Elephant calves appear more vulnerable during the dry months of the year, particularly in years of below average rainfall. Elephant calves are usually well protected. However, high-density aggregations of elephants around limited water sources during the dry season may deplete local food resources, forcing elephant herds to travel large distances between water and forage. Under these circumstances, elephant calves may become lost or separated from family groups, accounting for their high incidence in lion diet.