Multiple forms of DNA-dependent RNA polymerases have been described in several higher plants (5,7,11,13,16,18). RNA polymerases are compartmentalized within three organelles which include nuclei (2, 18), chloroplast (1), and mitochondria (4). We have shown previously that soybean nuclei contain at least two forms of RNA polymerase (2, 3). We have adopted the nomenclature introduced by Roeder and Rutter (14) and refer to these two forms as RNA polymerase I and RNA polymerase II, which relates to their order of elution from DEAE-cellulose. The two forms from soybean have characteristics similar to those from animals (10, 14) in that RNA polymerase I is insensitive to a-amanitin, whereas RNA polymerase II is inhibited by low concentrations of this fungal toxin (8,10,14). In animals, RNA polymerase I is localized in the nucleolus (15)