Ratos de Porão (Portuguese for "Basement Rats") is a Brazilian crossover thrash band from São Paulo.

Their core lineup of João Gordo on vocals and Jão on drums and later guitars has remained since virtually the band's beginning.

Ratos de Porão, or simply "RxDxPx", was formed in November 1981,[1] existing in the Brazilian (São Paulo city) punk rock scene (alongside bands such as Olho Seco, Cólera, Inocentes, Garotos Podres, and Lobotomia).

The Varukers and Swedish and Finnish bands such as Anti-Cimex and Kaaos, they started to write songs that criticized Brazilian society, a revolutionary concept at the time.

The line up was João Gordo (vocals), Mingau (guitar – later in many punk and pop bands in Brazil, currently playing in Ultraje a Rigor), Jabá (bass) and Jão (drums).

Jão switched over to playing guitar, and an old punk named Spaghetti (who later adopted a thrash metal sound) replaced him on drums.

With Harris Johns of Voivod and Tankard producing, the band's production quality improved substantially in contrast to their previous releases; the instrumentation was noticeably more technical.

With Harris Johns acting again as producer, their next album titled Anarkophobia was met with criticism by some fans for being the band's most metallic release to date, having considerably more complex and lengthy song compositions and more technical musicianship.

In 1992, RxDxPx released its first official live album, called Ao Vivo, with a corresponding music video for the song "Aids, Pop, Repressão" receiving heavy air play on Furia Metal of MTV (the Brazilian equivalent of Headbangers Ball).