Here we describe a method for preparing high-quality cDNA libraries from total RNA. By this method, double-stranded (ds) cDNA ligated with a specially designed ds adaptor is amplified by PCR using a modified T-primer and another primer corresponding to the outer part of the adaptor, The suppression PCR effect strongly inhibits the amplification of poly(A)- RNA, thereby reducing background, This method leads to amplification of high-quality cDNA, facilitating the construction of representative cDNA libraries from as little as 10-100 ng of total RNA. (C) 1997 Academic Press