Abstract: A method of identifying and quantifying small RNA molecules comprising a) isolating RNA molecules; b) ligating RNA adapter molecules onto the isolated RNA molecules to form RNA template molecules; c) forming complementary DNA molecules by transcribing the RNA template molecules; d) amplifying the complementary DNA molecules; e) obtaining sequence information of the complementary DNA molecules (and thereby the RNA from which it was derived); and f) obtaining quantity information of the complementary DNA molecules, wherein the quantity information of the DNA molecules reflects the quantity of the isolated RNA molecules is provided. Included in the invention is the identification of RNA molecules between 15 and 30 nucleotides in length.