Mother-of-one Emily Pringle, from Cheltenham, broke 27 bones, ruptured an artery in her neck and lost litres of blood when she was involved in a crash on the A40 last July.
Karl Kellner, 34, whose blood was one of five units that helped to save her life, has been introduced to the 42-year-old as part of a campaign to raise awareness of the need for men to give blood.
Married father Mr Kellner, from Stafford, had given blood just days before the crash at a local donation session.
Ms Pringle told her donor when they met at a donation centre in Birmingham: "Your blood played a major, major part in keeping me alive and I am very grateful."
Mr Kellner, a graphic designer, said: "I was quite nervous before the meeting but it was an amazing experience to meet someone that you have helped. It was a very special day and one I will remember forever.
"Every time I donate now, I will be thinking in the back of my mind that this is something that will change another person's life."
Ms Pringle added: "I owe people who donate blood my life. It's as simple as that. It's so important for people to donate regularly."
The number of men giving blood has fallen by almost a quarter in the last five years, new figures show.
According to NHS Blood and Transplant (NHSBT), there were 350,425 male donors in England in 2018-19, down 24.8% from 2013-14 when there were 466,346.
Men's blood can contain fewer antibodies against red and white blood cells because women often make antibodies while pregnant.
This means male blood can be more suitable for creating blood products used to treat patients.