Biosimilars or follow-on biologics are biopharmaceutical drugs that are similar to approved biological drugs. Biosimilars are different from other generic drugs in terms of raw material and their manufacturing process. Generic drugs are composed of small molecules. However, biosimilars are composed of more complex molecules, such as human insulin and monoclonal antibodies. Many biosimilars are derived from plants, animals, bacteria, viruses and yeast. It is produced by recombinant DNA technology and controlled gene expression methods. Biosimilar drugs are used in prevention and treatment of various severe diseases such as cancer, diabetes, autoimmune diseases, heart attacks, rheumatoid arthritis, oncology, growth hormone deficiency, chronic kidney failure, hematological disease and infectious disease. Biosimilars offer less costly treatment than other biological drugs and synthetic drugs.