Adult Gastrodiscus aegyptiacus are about 1..5 cm long and 0.5-0.7 cm broad. They have the flat body and the oval shape typical for most flukes, but their body is divided in a small, conical anterior part and a wider posterior part with numerous papillae arranged in transverse rows.
As other flukes they have no external signs of segmentation. The mouth ends in the pharynx, a muscular tube that allows sucking. The digestive system is blind (i.e. without anus: the only opening is the mouth) and not linear, as in most animals, but branched, ending in several blind ducts (called coeca). As most flukes, Gastrodiscus are simultaneous hermaphrodites, i.e. they have both male and female reproductive organs.
The eggs have an oval shape and are rather large (~110x180 micrometers), thin shelled and have a brownish color.