Meireles has stated that drawing was his main artistic medium until 1968, when he altogether abandoned expressionistic drawing in favor of designing things that he wanted to physically construct. A topic that he especially explored in his art was the concept of the ephemeral and the non-object, art that only exists with interaction, which prompted him to create installation pieces or situational art. This led to his Virtual Spaces project, which he began in 1968. This project was “based on Euclidian principles of space” and sought to show how objects in space can be defined by three different planes. He modeled this concept as a series of environments made to look like corners in rooms.
Following the military coup in 1964, Meireles became involved in political art. When Meireles was “first getting started as an artist,” governmental censorship of various forms of media, including art, was standard in Brazil. Meireles found ways to create art that was subversive but subtle enough to make public by taking inspiration from Dadaist art, which he notes had the ability to seem “tame” and “ironic.” In the early 1970s he developed a political art project that aimed to reach a wide audience while avoiding censorship called Insertions Into Ideological Circuits, which was continued until 1976. Many of his installation pieces since this time have taken on political themes, though now his art is “less overtly political.”
He was one of the founders of the Experimental Unit of the Museu de Arte Moderna in Rio de Janeiro in 1969 and in 1975, edited the art magazine Malasartes.
In 1999, Meireles was honoured with a Prince Claus Award and in 2008 he won the Velazquez Plastic Arts Award, presented by the Ministry of Culture of Spain.
An art project with political undertones that was designed to reach a mass-audience. This project manifested in multiple ways, two of the most well-known being the Coca-Cola project, and the Banknote project. Insertions Into Ideological Circuits was based upon three principles as defined by Meireles:
1) In society there are certain mechanisms for circulation (circuits);
2) these circuits clearly embody the ideology of the producer, but at the same time they are passive when they receive insertions into the circuit;
3) and this occurs whenever people initiate them.
The goal of Insertions… was to literally insert some kind of counter-information or critical thought into a large system of circulated information. Meireles inserted something that is physically the same, though ideologically different, into a pre-existing system in order to counteract the original circuit without disrupting it. The project was achieved by printing images and messages onto various items that were already widely circulated and which had value discouraging them being destroyed, such as Coca-Cola bottles (which were recycled by way of a deposit scheme) and banknotes. Meireles screen-printed texts onto the Coca-Cola bottles that were supposed to encourage the buyer to become aware of their personal role in a consumerist society.
The project simultaneously conveyed anti-imperialist and anti-capitalist messages.
Building off of that concept, Meireles also used money as a theme and produced his own replica banknotes and coins (1974–1978) which appeared very similar to genuine Brazilian and US currency but with zero denominations clearly written on them, e.g. Zero Dollar.
Meireles also wrote critiques of the Brazilian government on the banknotes, such as “Who killed Herzog?” (in reference to journalist Vladimir Herzog), “Yankees go home!” and “Direct elections.”