The year 1944 in science and technology involved some significant events, listed below.

• Hendrik van de Hulst predicts the 21 cm hyperfine line of neutral interstellar hydrogen.

• February 1 – Oswald T. Avery and colleagues publish the Avery–MacLeod–McCarty experiment^[1] showing that a DNA molecule can carry an inheritable trait to a living organism. This is important because many biologists thought that proteins were the hereditary material and nucleic acids too simple chemically to serve as genetic storage molecules.^[2]
• The lipopolysaccharide character of enteric endotoxins is elucidated by M. J. Shear.^[3]
• Erwin Schrödinger publishes What is Life?, containing conceptual discussion of the genetic code and of negentropy.
• Donald Griffin with G. W. Pierce demonstrate that bats use high-frequency sound in a technique which Griffin describes as echolocation.^[4]
• Last known evidence for existence of the Asiatic lion in the wild in Iran (Khuzestan province).^[5]

• February – Lars Onsager publishes the exact solution to the two-dimensional Ising model.^[6]
• Americium discovered by Glenn T. Seaborg, et al.

• August 7 – IBM dedicates the first program-controlled calculator, the Automatic Sequence Controlled Calculator, best known as the Harvard Mark I.

• March 18 – Last eruption of Mount Vesuvius.

• November 4 – The Whipple Museum of the History of Science is established when Robert Whipple presents his collection of scientific instruments to the University of Cambridge, England.
• C. Doris Hellman publishes her Columbia University thesis The Comet of 1577: Its Place in the History of Astronomy.

• John von Neumann and Oskar Morgenstern's book Theory of Games and Economic Behavior is published by Princeton University Press.

• November 19 – Minnesota Starvation Experiment begins.
• Hans Asperger describes Asperger syndrome.^[7]
• David S. Sheridan invents the disposable plastic tracheal tube catheter.^[8]
• Dorothea and Alexander Leighton's book Navajo at the Door is "the earliest example of applied medical anthropology".^[9]

• June 5 – Group Captain James Stagg correctly forecasts a brief improvement in weather conditions over the English Channel which permits the following day's Normandy landings to take place.
• August 6 – Ball lightning observed in Uppsala, Sweden.^[10]

• November 6 – Hanford Site in Washington (state) produces its first plutonium.

• March 27 – In Sweden, Ruben Rausing patents Erik Wallenberg's method of packaging milk in paper, origin of the company Tetra Pak.^[11]
• June 13 – First operational use of the German V-1 flying bomb, the first operational cruise missile, containing a gyroscope guidance system and propelled by a simple pulsejet engine.
• September 8 – First operational use of the German V-2 rocket, the first ballistic missile. On June 20 one has become the first man-made object to cross the Kármán line and reach the edge of space.^[12]
• December 9 – First flight of the Heinkel He 162 Volksjäger, the second jet engined fighter aircraft to be introduced by the Luftwaffe in World War II.
• First operational use of a snorkel on a submarine.

• Nobel Prizes
  • Physics – Isidor Isaac Rabi
  • Chemistry – Otto Hahn^[13]
  • Medicine – Joseph Erlanger, Herbert Spencer Gasser

• February 8 – Howard Dalton (died 2008), English microbiologist.
• February 15 – Sigurd Hofmann, German physicist.
• March 7 – Michael Rosbash, American geneticist and chronobiologist, recipient of the Nobel Prize in Physiology or Medicine.
• June 1 – Colin Blakemore, English neurobiologist (died 2022).
• June 5 – Whitfield Diffie, American cryptographer.
• June 6 – Phillip Allen Sharp, American geneticist and molecular biologist, recipient of the Nobel Prize in Physiology or Medicine.
• June 22 – Gérard Mourou, French electrical engineer, recipient of the Nobel Prize in Physics.
• July 13 – Ernő Rubik, Hungarian inventor and architect.
• August 24 – Gregory Jarvis (died 1986), American astronaut.
• October 11 – William T. Greenough (died 2013), American neuroscientist.
• October 16 – Elizabeth Loftus, American psychologist.
• October 21 – Jean-Pierre Sauvage, French coordination chemist, recipient of the Nobel Prize in Chemistry.
• December 19 – Richard Leakey (died 2022), Kenyan palaeoanthropologist.
• December 28 – Kary Mullis (died 2019), American biochemist, recipient of the Nobel Prize in Chemistry.

• January 19 – Emily Winifred Dickson (born 1866), British gynaecologist.^[14]
• January 20 – James McKeen Cattell (born 1860), American psychologist.
• February 8 – Bernard Sachs (born 1858), American neurologist.
• March – John R.F. Jeffreys (born 1918), British mathematician and cryptanalysist.
• March 2 – Ida Maclean (born 1877), English biochemist.
• March 5 – Ernst Cohen (born 1869), Dutch Jewish chemist (in Auschwitz concentration camp).
• March 29 – Grace Chisholm Young (born 1868), English mathematician.
• August 23 – Margarete Zuelzer (born 1877), German Jewish microbiologist (in Westerbork transit camp).
• June 18 – Harry Fielding Reid (born 1859), American geophysicist.
• July 25 – Jakob Johann von Uexküll (born 1864), Baltic German pioneer of biosemiotics.^[15]
• November 2 – Thomas Midgley Jr. (born 1889), American chemist and inventor.
• November 22 – Sir Arthur Eddington (born 1882), English astrophysicist.