The efficient extraction and purification of viral RNA is critical for downstream molecular applications such as the sensitive and specific detection of virus in clinical samples, virus gene cloning and expression, gene sequencing, or quantification of avian influenza (AI) virus by molecular methods from experimentally infected birds. Samples can generally be divided into two types: enriched (e.g., virus stocks) and non-enriched (e.g., clinical). Clinical samples, which may be tissues or swab material, are the most difficult to process due to the complex sample composition and possibly low virus titers. In this chapter, two well-established procedures for the extraction of AI virus RNA from common clinical specimen types and enriched virus stocks will be presented.