The signature feature of the species is its huge, bulbous bill, which is straw-coloured with erratic greyish markings. A male will weigh on average around 5.6 kg (12 lb) and is larger than a typical female of 4.9 kg (11 lb). Weight has reportedly ranged from 4 to 7 kg (8.8 to 15.4 lb). Length from tail to beak can range from 100 to 140 cm (39 to 55 in) and wingspan is 230 to 260 cm (7 ft 7 in to 8 ft 6 in). The shoebill is a tall bird, with a typical height range of 110 to 140 cm (43 to 55 in) and some specimens reaching as much as 152 cm (60 in). All that is known of Eremopezus is that it was a very large, probably flightless bird with a flexible foot, allowing it to handle either vegetation or prey. It has been suggested that the enigmatic African fossil bird Eremopezus was a relative too, but the evidence for that is unconfirmed. So far, two fossil relatives of the shoebill have been described: Goliathia from the early Oligocene of Egypt and Paludavis from the Early Miocene of the same country. A recent DNA study reinforces their membership of the Pelecaniformes.

Microscopic analysis of eggshell structure by Konstantin Mikhailov in 1995 found that the eggshells of shoebills closely resembled those of other Pelecaniformes in having a covering of thick microglobular material over the crystalline shells. More recently, the shoebill has been considered to be closer to the pelicans(based on anatomical comparisons) or the herons (based on biochemical evidence Hagey et al., 2002). Traditionally allied with the storks (Ciconiiformes), it was retained there in the Sibley-Ahlquist taxonomy which lumped a massive number of unrelated taxa into their 'Ciconiiformes'. The shoebill was known to both ancient Egyptians and Arabs but was not classified until the 19th century, after skins and eventually live specimens were brought to Europe.

Shoebill habitat