Gene synthesis is an invaluable technique in synthetic and molecular biology for synthesis of artificial genes, operons, and even genomes. In many cases the traditional methods for obtaining functional DNA sequences through cloning are not applicable due to the novelty of genetic material. Here, we describe the simple and economical DNA synthesis method based on USER™ technology. The method consists of (1) synthesis of building blocks up to 500 bp; (2) assembly of genes up to 3 kb; (3) error correction reassembly; and (4) assembly of operons up to 15 kb if needed.