The propensity of Taq polymerase to add 3′-A overhangs (1,2) to PCR-amplified DNA has made possible a simple method for cloning PCR products into a T-vector (Invitrogen [San Diego, CA]; 3–5). Here we present a related strategy that uses T-linkers to add sequences, such as restriction sites, to the ends of PCR products (see Note 1). A single base T overhang at the end of a synthetic double-stranded oligonucleotide linker allows ligation of the linker to the unpolished ends of a PCR product. This avoids the expense of adding the “extra” sequences to sequence-specific primers.