The goal of this work is determining the bacterial community of bacteria to the decomposition of the liver in the field. To achieve this goal three sites with rotten liver in the Parque Nacional Metropolitano, Panamá City, Panamá, were set from November 1999 to December 2000. A bacterial sample on each liver surface was taken daily. We obtained 31 bacterium species, 22 at the rainy season and all of them at the dry season. They were grouped according to the season in three groups of bacterium: one of them only presents at the dry season, the other one with the greater number at the dry season, and the last one with the greater number of bacterium at the rainy season. We discuss the environmental implications of each group and its importance in the attraction of the screwworm Cochliomyia hominivorax.