Astrophysicist Marica Branchesi, whose work helped lead to the detection of gravitational waves last year, and surgeon Giuliano Testa, who led a groundbreaking trial of uterus transplants, were both honoured in the prestigious ranking.
Branchesi was partly responsible for the Nobel Prize-winning detection of gravitational waves, an achievement the US-based news magazine described as "monumental".
"It took Albert Einstein to predict the existence of gravitational waves-ripples in space-time that occur when objects like black holes collide. It took Marica Branchesi to make sure we actually saw the evidence of such a crack-up," wrote Time journalist Jeffrey Kluger in his profile of the Italian.
Detectors in the US had recorded gravitational waves three times, but thanks to Branchesi, teams of astronomers and physicists worked together using telescopes across the world so that in August 2017, a cosmic event was detected in both gravitational waves and light for the first ever time.
READ MORE: The 2017 Nobel Physics Prize explained
Branchesi works at the Gran Sasso laboratory of the National Institute of Nuclear Physics (INFN) and is also vice president of the International Astronomical Union Gravitational Wave Astrophysics Commission.
Her inclusion in the list was the latest in a series of accolades for the astrophysicist, who in December was named by Nature as one of 2017's 'Ten people who mattered this year'. After that honour, then prime minister Paolo Gentiloni told Branchesi: "You make Italy proud."
Surgeon Giuliano Testa's Time profile was written by an anonymous mother who was born without a uterus but successfully gave birth to the first baby born via uterus transplant in the US (the first ever womb transplant baby was born in Sweden in 2014), after taking part in Testa's clinical trial. A second baby was also born to another woman as a result of the same trial.
"The experience was not without setbacks. But through it all, Dr. Testa was a pillar of strength and assurance. And that confidence was contagious," the woman wrote.
Having studied in Padua, Testa now works at the Baylor University Medical Center at Dallas where he is the chief of abdominal transplantation.
Other notable names on Time's list, which has been published since 1999, included the student survivors of the Parkland school shooting who have since campaigned for better gun control, Donald Trump, the UK's Prince Harry and his fiancee Meghan Markle, and actress Nicole Kidman.
Update: This article was amended on April 19th, after an earlier version stated that Branchesi was the only Italian included on the list.