Monoclonal antibodies (MAbs) are the magic bullet molecules that have been crowned as one of the personalized medicines due to their high degree of specificity characteristics on the diseases. MAbs products have become top-selling biopharmaceutical productsBiopharmaceutical products for many consecutive years including in the year 2023 led by Keytruda® (pembrolizumab) with a revenue of USD 12.00 billion. Cancer, rheumatoid arthritis, psoriasis, and Crohn’s diseases are the main target of MAbs through their effective and efficient action. The remarkable effect of MAbs on cancer has led to the fastest-growing biological extent of production at an affordable price. This can be achieved by the introduction of low-cost products, namely, biosimilars. A biosimilar product possesses high similarity toward the originator which underwent less expensive cost and shorter clinical trials. The biological activity of biosimilar biologics is comparable toward the original product. Biosimilars are marketed following the exclusive patent of the originator. To date, 37 biosimilar MAbs have been approved by the United States Food and Drug Administration with 10 of them using adalimumab under the licensing of Humira®. This chapter covers an update of the biosimilar MAbs that have been approved together with their description focusing on of infliximab, adalimumab, bevacizumab, trastuzumab, and rituximab.