Juan Carlos Finlay ( December 3 1833-1915), was a Cuban physician and scientist.

Juan Carlos Finlay was born in Puerto Principe , Cuba. He changed his name to Carlos Juan Finlay later in his life. In 1853 he attended Jefferson Medical College in Philadelphia, Pennsylvania. He graduated in 1855, and completed his studies in Havana, and in Paris. Afterwards he settled in Cuba and opened a medical practice.

In 1865 Dr. Finlay sent a paper to the Academy of Sciences in Havana outlining his theory on weather conditions and the yellow fever disease. Carlos Finlay became famous for his work in identifying the mosquito as a carrier of the deadly yellow fever germ. His theory was followed by the recommendation to control the mosquito population as a way to control the spread of yellow fever. His work, carried out during the 1870's finally came to prominence in 1900. He was the first to theorize in 1881 that a mosquito was the way by which yellow fever was transmitted; a mosquito that bites a victim of the disease could bite a healthy person and spread the disease. His hypothesis was proven nearly twenty years later by the Walter Reed Commission of 1900.

In the words of General Leonard Wood, a physician and U.S. military governor of Cuba in 1900: "The confirmation of Dr. Finlay's doctrine is the greatest step forward made in medical science since Jenner's discovery of the vaccination."