The present invention relates to liquid formulations of poxvirus in particular vaccinia virus stable during storage. Such stable liquid formulations comprise a) a poxvirus preferably a vaccinia virus b) a pharmaceutically acceptable buffer c) a monovalent salt d) a pharmaceutically acceptable disaccharide or sugar alcohol and e) a pharmaceutically acceptable chelating agent wherein the pH of the formulation is comprised between 6.5 and 8.5.