The year 1949 in science and technology involved some significant events, listed below.

• January 26 – The Hale Telescope at Palomar Observatory in California, the largest aperture optical telescope in the world for 28 years, sees first light.
• June 14 – Albert II, a rhesus monkey, becomes the first mammal in space, in a U.S.-launched V-2 rocket, reaching an altitude of 83 miles (134 km) but dying on impact after a parachute failure.

• Radiocarbon dating technique discovered by Willard Libby and his colleagues at the University of Chicago—work for which Libby will receive the Nobel Prize in 1960.
• A group including Dorothy Hodgkin publish the three-dimensional molecular structure of penicillin, demonstrating that it contains a β-lactam ring.^[1][2]

• April – Manchester Mark 1 computer operable at the University of Manchester in England.
• May 6 – EDSAC, the first practicable stored-program computer, runs its first program at University of Cambridge in England, to calculate a table of squares.^[3]

• August 5 – Ambato earthquake in Ecuador, measuring 6.8 on the Richter magnitude scale.^[4]
• Patomskiy crater in Siberia is discovered by Russian geologist Vadim Kolpakov.

• Herbert Butterfield publishes The Origins of Modern Science, 1300-1800.

• Ákos Császár discovers the Császár polyhedron.
• D. R. Kaprekar discovers the convergence property of the number 6174.

• The use of lithium salts to control mania is rediscovered by Australian psychiatrist John Cade, the first mood stabilizer.^[5]
• First implant of intraocular lens, by Sir Harold Ridley
• First Sixteen Personality Factor Questionnaire, a self-report personality test, released.

• January 11 – Los Angeles, California receives its first recorded snowfall.

• Gilbert Ryle's book The Concept of Mind, a founding document in the philosophy of mind, is published.

• Freeman Dyson demonstrates the equivalence of the formulations of quantum electrodynamics existing at this time,^[6] incidentally inventing the Dyson series.^[7]
• The Lanczos tensor is introduced in general relativity by Cornelius Lanczos.^[8]
• Pauli–Villars regularization is first published.^[9]

• J. B. S. Haldane proposes the Darwin as a unit of evolutionary change.^[10]
• Konrad Lorenz publishes King Solomon's Ring (Er redete mit dem Vieh, den Vögeln und den Fischen).

• Nobel Prizes
  • Physics – Hideki Yukawa
  • Chemistry – William Francis Giauque
  • Medicine – Walter Rudolf Hess, Antonio Caetano De Abreu Freire Egas Moniz

• January 25 – Paul Nurse, English cell biologist, winner of the Nobel Prize in Physiology or Medicine.
• February 1 – Alice Alldredge, Australian-born oceanographer.
• February 17 – Peter Piot, Belgian microbiologist and epidemiologist.
• February 19 – Danielle Bunten Berry, born Dan(iel Paul) Bunten (died 1998), American software developer.
• February 22 – Tullio Pozzan (died 2022), Italian biochemist.
• March 28 – Michael W. Young, American geneticist and chronobiologist, winner of the Nobel Prize in Physiology or Medicine.
• April 5 – Judith Resnik (died 1986), American astronaut.
• April 18 – Yasumasa Kanada, Japanese mathematician.
• May 24 – Tomaž Pisanski, Slovenian mathematician.
• May 26 – Ward Cunningham, American computer programmer.
• June 2 – Heather Couper (died 2020), English astronomer.
• July 23 – Andrew Odlyzko, Polish-born American mathematician.
• August 31 – H. David Politzer, American physicist, winner of the Nobel Prize in Physics.
• November 6 – John Zarnecki, English space scientist
• November 24 – Sally Davies, English Chief Medical Officer.
• Michael Houghton, British-born virologist, winner of the Nobel Prize in Physiology or Medicine.

• February 22 – Félix d'Herelle (died 1873), French-Canadian microbiologist, a co-discoverer of bacteriophages.
• April 28 – Robert Robertson (born 1869), British chemist.
• May 27
  • Ægidius Elling (born 1861), Norwegian gas turbine pioneer.
  • Martin Knudsen (born 1871), Danish physicist.
• August 5 – Ernest Fourneau (born 1872), French medicinal chemist.