Collagen mRNA has already been purified and characterized by us. Its purity has now been enhanced by two different methods. Gel electrophoresis shows in either method, a single peak with the same mobility already reported: 1.05×106 daltons. Base composition analyses of collagen mRNA purified by either method were almost identical. Chemical analyses of the isolated polyadenylic acid stretch show that it is, 0.48×105 daltons-long, (about 140 nucleotides-long), contains 75% AMP, and is located at the 3′ end of the polymer.