A set of four computer programs that search DNA sequence data files for transfer RNA genes have been written in IBM (Microsoft) BASIC for the IBM personal computer. These programs locate and plot predicted secondary structures of tRNA genes in the cloverleaf conformation. The set of programs are applicable to eukaryotic tRNA genes, including those containing intervening sequences, and to prokaryotic and mitochondrial tRNA genes. In addition, two of the programs search up to 150 residues downstream of tRNA gene sequences for possible eukaryotic RNA polymerase III termination sites comprised of at least four consecutive T residues. Molecular biologists studying a variety of gene sequence and flanking regions can use these programs to search for the additional presence of tRNA genes. Furthermore, investigators studying tRNA gene structure-to-function relationships would not need to do extensive restriction mapping to locate tRNA gene sequences within their cloned DNA fragments.