Severo Ochoa was a prominent Spanish-American biochemist recognized for his significant contributions to molecular biology and genetics. Born in 1905 in Luarca, Asturias, Spain, he displayed an extraordinary aptitude for science early on. He pursued his education in medicine at the University of Madrid, where he developed a keen interest in biochemistry. Ochoa’s career was marked by numerous collaborations and research endeavors, which led him to emigrate to the United States due to the Spanish Civil War. He later became a naturalized American citizen. Ochoa is perhaps best known for his discovery of the mechanisms of RNA synthesis, which was foundational in understanding how genetic information is expressed within living organisms. His work focused on the enzyme RNA polymerase and its role in the production of RNA from DNA. This pivotal research not only advanced our knowledge of gene expression but also opened up new avenues in genetics and molecular biology, contributing to the fields of medicine and biotechnology. For his groundbreaking research, Ochoa received numerous accolades, including the Nobel Prize in Physiology or Medicine in 1959, which he shared with Arthur Kornberg. His legacy lives on through his influence on future generations of scientists and the advancements in genetic research that have stemmed from his findings. The impact of his work continues to be felt in many areas of modern biology and medicine. Severo Ochoa was a Spanish-American biochemist known for his significant contributions to molecular biology. His research focused on RNA synthesis, particularly the role of RNA polymerase in gene expression. Ochoa's legacy includes a Nobel Prize and influence on future generations of scientists in genetics and molecular biology.