Sarcosuchus (/ˌsɑːrkoʊˈsuːkəs/), from Ancient Greek σάρξ (sárx), meaning "flesh", and σούχος (soúkhos), meaning "crocodile", is an extinct genus of crocodyliform that lived during the Early Cretaceous, from the late Hauterivian to the early Albian stages, 130 to 112 million years ago of what is now Africa and South America. It was one of the largest pseudosuchians, with the largest specimen of S. imperator reaching approximately 9–9.5 metres (29.5–31.2 ft) long and weighing up to 3.45–4.3 metric tons (3.80–4.74 short tons). It is known from two species; S. imperator from the early Albian Elrhaz Formation of Niger, and S. hartti from the Late Hauterivian of northeastern Brazil. Other material is known from Morocco and Tunisia and possibly Libya and Mali.

The first remains were discovered during several expeditions led by the French paleontologist Albert-Félix de Lapparent, spanning from 1946 to 1959, in the Sahara. These remains were fragments of the skull, vertebrae, teeth, and scutes. In 1964, an almost complete skull was found in Niger by the French CEA, but it was not until 1997 and 2000 that most of its anatomy became known to science, when an expedition led by the American paleontologist Paul Sereno discovered six new specimens, including one with about half the skeleton intact including most of the spine.

Sarcosuchus is a distant relative of living crocodilians, with fully grown individuals estimated to have reached up to 9 to 9.5 m (29.5 to 31.2 ft) in total length and 3.45 to 4.3 metric tons (3.80 to 4.74 short tons) in weight. It had somewhat telescoped eyes and a long snout comprising 75% of the length of the skull. There were 35 teeth in each side of the upper jaw, while in the lower jaw there were 31 teeth in each side. The upper jaw was also noticeably longer than the lower one, leaving a gap between them when the jaws were shut that created an overbite. In young individuals the shape of the snout resembled that of the living gharial, but in fully grown individuals it became considerably broader.

Sarcosuchus has an expansion at the end of its snout known as a bulla, which has been compared with the ghara seen in gharials. However, unlike the ghara, which is only found in male gharials, the bulla is present in all Sarcosuchus skulls that have been found so far, suggesting that it was not a sexually dimorphic trait. The purpose of this structure is not known.

The osteoderms, also known as dermal scutes, of Sarcosuchus were similar to those goniopholodids like Sunosuchus and Goniopholis; they formed an uninterrupted surface that started in the posterior part of the neck down to the middle of the tail as is seen in Araripesuchus and other basal crocodyliforms; this differs from the pattern seen in living crocodiles, which presents discontinuity between the osteoderms of the neck and body.

A common method to estimate the size of crocodiles and crocodile-like reptiles is the use of the length of the skull measured in the midline from the tip of the snout to the back of the skull table, as in living crocodilians there is a strong correlation between skull length and total body length in subadult and adult individuals irrespective of their sex. This method was used by Sereno et al. (2001) for Sarcosuchus due to the absence of a complete enough skeleton. Two regression equations were used to estimate the size of S. imperator, they were created based on measurements gathered from 17 captive gharial individuals from northern India and from 28 wild saltwater crocodile individuals from northern Australia, both datasets supplemented by available measurements of individuals over 1.5 m (4.92 ft) in length found in the literature. The largest known skull of S. imperator (the type specimen) is 1.6 m (5.25 ft) long (1.5 m (4.92 ft) in the midline), and it was estimated that the individual it belonged to had a total body length of 11.65 m (38.2 ft). Its snout-vent length of 5.7 m (18.7 ft) was estimated using linear equations for the saltwater crocodile and in turn this measurement was used to estimate its body weight at 8 metric tons (8.8 short tons). This shows that Sarcosuchus was able to reach a maximum body size not only greater than previously estimated but also greater than that of the Miocene Rhamphosuchus, the Late Cretaceous Deinosuchus, and the Miocene Purussaurus according to current estimates at that time.

However, extrapolation from the femur of a subadult individual as well as measurements of the skull width further showed that the largest S. imperator was significantly smaller than was estimated by Sereno et al. (2001) based on modern crocodilians. O'Brien et al. (2019) estimated the length of the largest S. imperator specimen at nearly 9 metres (29.5 ft) and body mass at 3.45 metric tons (3.80 short tons) based on longirostrine crocodylian skull width to total length and body width ratio. The highest upper quartile reconstructed length and body mass for the specimen is 9.5 metres (31.2 ft) and 4.3 metric tons (4.7 short tons), respectively.

Sarcosuchus is commonly classified as part of the clade Pholidosauridae, a group of crocodile-like reptiles (Crocodyliformes) related but outside Crocodylia (the clade containing living crocodiles, alligators and gharials). Within this group it is most closely related to the North American genus Terminonaris. Most members of Pholidosauridae had long, slender snouts and they all were aquatic, inhabiting several different environments. Some forms are interpreted as marine, capable of tolerating saltwater while others, like Sarcosuchus, were freshwater forms. The most primitive members of the clade, however, were found in coastal settings, zones mixing freshwater and marine waters. Sarcosuchus stands out among pholidosaurids for being considered a generalist predator, different from most known members of the clade which were specialized piscivores. A 2019 study found it to be in a more derived position in Tethysuchia, being phylogenetically closer to Dyrosauridae.