The Colosseum had a wide range of uses, including the famous gladiator fights and a variety of spectacular events. These spectacles, known as munera, were usually financed by citizens rather than the state. Although they had a strong religious component, they also served as a display of power and prestige for the sponsoring families, and became extremely popular among the common population. Another prominent event was the hunting of animals, known as venatio, which featured a diversity of wild beasts, many of them imported from Africa, such as rhinoceroses, hippopotamuses, elephants, giraffes, lions, panthers, leopards, crocodiles and ostriches. These battles and hunts took place in scenarios with trees and movable structures.

Sometimes these events were held on a grandiose scale; it is related that Trajan commemorated his victories in Dacia in 107 with games that involved 11,000 animals and 10,000 gladiators, and lasted for 123 days. The public or the emperor had the authority to decide the fate of a wounded gladiator by showing a thumbs-up or thumbs-down, representing the life or death of the defeated combatant.

During the early days of the Colosseum, ancient writers mentioned that the building was used to stage naumachiae, or mock naval battles. Reports of the inaugural games organized by Titus in the 80s describe the flooding of the lower level to showcase horses and bulls that had previously been trained in swimming. There is also mention of a reenactment of a famous naval battle between Corfu Greeks and Corinthians. However, this has sparked debate among historians, as it is unclear how the arena would be made waterproof or whether there would be sufficient space for the movement of warships. Some suggest that these references may relate to another location or that the Colosseum originally had a floodable channel running to its central axis before being replaced by the hypogeum.

The poet Martial also made reference to these inaugural games, specifically to an epic gladiatorial fight between Vero and Priscus. Both combatants faced off before the emperor Titus and, despite their grueling battle, neither managed to defeat the other. This unusual draw was acclaimed by the crowd and led the emperor to spare their lives. This exceptional event was recorded in Martial's work called "Liber spectaculorum".

In addition to fights and hunts, representations of natural landscapes were performed in the arena, known as sylvae. Painters, technicians and architects created simulations of forests with real trees and shrubs that were planted on the arena floor. Animals were introduced to populate these landscapes and amaze the audience. These settings were sometimes used simply to show natural environments to the urban population, or as a backdrop for hunting scenes and depictions of mythological episodes. Occasionally, they were used for executions in which the condemned man played the role of the hero of the story and was executed in a grisly but mythological manner, either by being devoured by beasts or burned to death.