Therizinosaurs spanned a large range of sizes, from the smaller Beipiaosaurus (2.2 m (7.2 ft) long) and Jianchangosaurus (2 m (6.6 ft) long) to the large-sized 6–7 m (20–23 ft) long Segnosaurus and Suzhousaurus.
Therizinosaurus itself, obtained the top dimensions of the group, growing up to 10 m (33 ft) long and weighing over 5 t (11,000 lb), dimensions that make the genus among the largest-known theropods.

Therizinosaurs had a very distinctive, often confusing set of characteristics.
Their long necks, wide torsos, and hind feet with four toes used in walking resembled those of basal sauropodomorph dinosaurs.
Their unique hip bones, which pointed backwards and were partially fused together, initially reminded paleontologists of the "bird-hipped" ornithischians.
Among the most striking characteristics of therizinosaurs are the enormous claws on their hands, which reached lengths of around one meter in Therizinosaurus.
The unusual range of motion in therizinosaur forelimbs, which allowed them to reach forward to a degree other theropods could not achieve, also supports the idea that they were mainly herbivorous.
Therizinosaurs may have used their long reach and strongly curved claws to grasp and shear leafy branches, in a manner similar to large mammals that lived later on, such as chalicotheres, ground sloths, great apes, and giant pandas.
Skin impressions from Beipiaosaurus indicate that therizinosaurs were covered with a coat of primitive, down-like feathers similar to those seen in the compsognathid Sinosauropteryx, as well as longer, simpler, quill-like feathers that may have been used in display.
Therizinosaurs spanned a large range of sizes, from the smaller Beipiaosaurus (2.2 m (7.2 ft) long) and Jianchangosaurus (2 m (6.6 ft) long) to the large-sized 6–7 m (20–23 ft) long Segnosaurus and Suzhousaurus. Therizinosaurus itself, obtained the top dimensions of the group, growing up to 10 m (33 ft) long and weighing over 5 t (11,000 lb), dimensions that make the genus among the largest-known theropods.
Therizinosaurs had a very distinctive, often confusing set of characteristics. Their long necks, wide torsos, and hind feet with four toes used in walking resembled those of basal sauropodomorph dinosaurs. Their unique hip bones, which pointed backwards and were partially fused together, initially reminded paleontologists of the "bird-hipped" ornithischians. Among the most striking characteristics of therizinosaurs are the enormous claws on their hands, which reached lengths of around one meter in Therizinosaurus. The unusual range of motion in therizinosaur forelimbs, which allowed them to reach forward to a degree other theropods could not achieve, also supports the idea that they were mainly herbivorous. Therizinosaurs may have used their long reach and strongly curved claws to grasp and shear leafy branches, in a manner similar to large mammals that lived later on, such as chalicotheres, ground sloths, great apes, and giant pandas. Skin impressions from Beipiaosaurus indicate that therizinosaurs were covered with a coat of primitive, down-like feathers similar to those seen in the compsognathid Sinosauropteryx, as well as longer, simpler, quill-like feathers that may have been used in display.
Therizinosauria