Histories extracted from various organs of the rat have been fractionated by electrophoresis on Polyacrylamide gels. The most convenient reagents to form the gel were selected and the effects of varying concentrations of these reagents on the resolution of histones were investigated. Optimum conditions for the separation of histones were found to be the same as those for starch gel electrophoresis. More consistent results were obtained with the use of Polyacrylamide gels because these gels were equilibrated to constant pH and ionic strength prior to electrophoresis and the gels were electrophoretically destained to demonstrate the histone bands.