It has been 20 years since New Zealand Blood Service (NZBS) was established, and it's marking the milestone with a thankful heart.
More than 600,000 donors have helped out, with every whole blood donation potentially saving up to three lives.
Chief executive officer Sam Cliffe says the NZBS is celebrating recipients, staff and donors.
"It's an opportunity to say a national big heartfelt thank you to every one of the 600,000 people who've donated over the past 20 years," she said.
Ms Cliffe says there are more than 120,000 people are on the NZBS data base who continue to donate.
But it's a challenge to find more as people are constantly retiring as donors due to age, illness or if they move away.
"We've put a huge amount of focus into programmes to attract, recruit and retain new donors - we lose donors from our donor panel every year," she said.
Health Minister Dr David Clark will be joined by milestone donors and recipients as well as long-serving staff to celebrate the milestone.