The positive-sense genome can act as messenger RNA (mRNA) and can be directly translated into viral proteins by the host cell's ribosomes.

Positive-strand RNA viruses are divided between the phyla Kitrinoviricota, Lenarviricota, and Pisuviricota (specifically classes Pisoniviricetes and Stelpavirictes) all of which are in the kingdom Orthornavirae and realm Riboviria.

[4] Coronaviruses have the largest known RNA genomes, between 27 and 32 kilobases in length, and likely possess replication proofreading mechanisms in the form of an exoribonuclease within nonstructural protein nsp14.

[4] Numerous positive-strand RNA viruses can undergo genetic recombination when at least two viral genomes are present in the same host cell.

RNA recombination appears to be a major driving force in determining genome architecture and the course of viral evolution among Picornaviridae (e.g.

[11] In the Retroviridae (e.g. HIV), genome damage appears to be avoided during reverse transcription by strand switching, a form of recombination.

[18] Positive-strand RNA viruses are found in three phyla: Kitrinoviricota, Lenarviricota, and Pisuviricota, each of which are assigned to the kingdom Orthornavirae in the realm Riboviria.

Based on phylogenetic analysis of RdRp, all other RNA viruses are considered to comprise a sister clade in relation to Lenarviricota.

The phylum contains three classes, two of which contain only +ssRNA viruses: Pisoniviricetes, which contains nidoviruses, picornaviruses, and sobeliviruses, and Stelpaviricetes, which contains potyviruses and astroviruses.