Exciting advances in biotechnology have led to the development of innovative biological products to improve health care. In this review article, the major techniques of product development and manufacturing in biotechnology are discussed, with a focus on recombinant DNA technology. In addition, monoclonal antibody, nucleotide blockade, polymerase chain reaction, antisense, and gene therapy technologies will be defined briefly. For recombinant-DNA technology, the issues of gene isolation, gene cloning, protein expression, scale-up (manufacturing), and quality assurance are addressed. The 16 approved products and the research pipeline are characterized. In addition, major usage issues for biological products are noted. This review serves as an introduction to the science and applications of biotechnology present and future.