Yumi's Cells () is a 2021 South Korean television series directed by Lee Sang-yeob and starring Kim Go-eun, Ahn Bo-hyun, and Park Jin-young. Based on the eponymous webtoon, it is a cell-based psychological romance that unravels the daily life of an ordinary office worker Yumi through the eyes of the cells in her head. The series premiered on tvN on September 17, 2021, and aired every Friday and Saturday at 22:50 (KST). It was also released simultaneously on both online streaming services TVING and iQIYI.
On September 8, 2021, TVING announced that the drama had sold broadcast rights in more than 160 countries around the world, including Europe, North America and Southeast Asia.
The second season premiered exclusively on TVING on June 10, 2022, releasing two episodes every Friday at 16:00 (KST). It was later aired on tvN from November 16, 2022, every Wednesday and Thursday at 22:30 (KST). On September 15, 2022, it was announced that season 2 had been sold to Amazon Prime Video for broadcasting in Japan.
The third season will premiere on TVING on April 13, 2026, releasing two episodes every Monday at 18:00 (KST); it will also air on tvN every Monday and Tuesday at 20:50 (KST).
The drama tells the story of an ordinary office worker from the perspective of the brain cells in her head that control her every thought, feeling and action.
Yumi (Kim Go-eun) is an ordinary woman whose Love Cell has fallen into a coma following the shock of a failed relationship. When she meets Goo Woong (Ahn Bo-hyun), a game developer, his simple and honest personality wakes up Yumi's Love Cell.
After parting with Goo Woong, Yumi starts a new relationship with her co-worker Babi (Jinyoung). In the meantime, she rekindles her dream of becoming a writer.
Yumi, now in her mid-30s, has become a renowned romance novelist, but she feels a sense of emptiness. The arrival of Shin Soon-rok (Kim Jae-won) plunges her life into a new mix of joy and despair.
On December 31, 2020, it was reported that webtoon Yumi's Cells published on Naver by Lee Dong-gun from 2015 to 2020 with 3.2 billion accumulated views was being made into a television series and Kim Go-eun was confirmed as the female lead. On March 10, 2021, media reported that Ahn Bo-hyun had received an offer for the part of Yu-mi's first boyfriend, Goo Woong, which was confirmed on April 27 with the final line-up, which also included Lee Yu-bi, Park Ji-hyun and Choi Min-ho.
On July 22, 2021, Jinyoung joined the cast, appearing from episode 8 onwards as Yoo Babi; in the second season the character was promoted to male lead. The second season also features special appearances by Shin Ye-eun, P.O, and Jeon Seok-ho.
The production of the third season was announced on March 31, 2025. Kim Jae-won joined the cast as Shin Soon-rok; new characters played by Choi Daniel and Cho Hye-jung were also introduced.
The first two seasons started production simultaneously. Filming began in April 2021 and ended the following December. While the first season wanted to faithfully adapt the webtoon, with the second one the director and the writers took a different approach, given the polarization of opinions on Babi by the readers of the original work. As Babi flirts with another woman while he is dating Yumi, Jinyoung commented that one of his sisters had asked him if he was really sure about accepting the part and that, with the help of the director and Kim Go-eun, he had tried to show Babi's infinite love for Yumi to try to make people hate him less. Since the third season had not yet been confirmed at the time of filming and wanting to highlight Lee Dong-gun's creativity, the scenes of Yumi's third boyfriend, Shin Soon-rok, were therefore adapted for Babi.
Filming of the third season took place from June to October 2025.
Yumi's Cells was produced using a new format which combined live-action and 3D animation. It was the first time such a format was used to produce a TV series while using the Unreal Engine as its source. The 3D animation was produced by Locus Corporation (also known as Sidus Animation Studios), the producer of Red Shoes and the Seven Dwarfs.
Yumi's Cells has been praised for its refreshing and humorous depiction of the daily life of an ordinary office worker. The first season was praised for its casting, the actors' performances, the faithful adaptation of the webtoon, and the use of 3D animation to depict the cells, although some critics stated that the relatively new attempt to integrate live action and animation could be a barrier for those who were not already fans of the original work. This latter reason was cited as the likely cause of the ratings, which were considered disappointing for its quality.
After the release of the first two episodes of the second season, TVING recorded the highest number of paying subscribers of any of its original dramas, quadrupling the number of subscribers since the premiere of the previous season. Yumi's Cells 2 was praised for its greater maturity and evolution in the actors' performances, and was ranked 7th in the best series of 2022 by Cine21, who praised it for not losing its momentum and for realistically weaving together character growth and romance. Indiatoday applauded the chemistry between Kim Go-eun and Jinyoung, but felt that Babi's character had been poorly handled, especially in the second half.
The release of the second season on June 10 saw the number of TVING's paid subscribers increasing by more than 60% from the first to the second week, and the series took first place among all the platform original contents for five weeks in a row.