Most people have two kidneys but can lead a normal life with just one.
Kidneys will only be accepted from donors who have passed a number of very thorough medical tests. There can still be a small risk that the donor could have problems after they donate their kidney.
If you pass all the tests, you can donate one of your kidneys to another person.
When you have your operation, the surgeon will leave your best kidney in you. Your other kidney will be transplanted into your recipient.
Most donors do not have any change in their health after donating a kidney.
About 3 in 1000 donors will go on to develop end-stage kidney disease. This is considered to be low risk.
About 2 in 1000 people who do not donate a kidney will develop end-stage kidney disease. This is also considered low risk.
For comparison, about 50 in 1000 New Zealanders will develop bowel cancer at some point in their lives, and about 100 in 1000 New Zealand women will develop breast cancer. These are considered to be high risks.
Most female donors who become pregnant after donating a kidney can have normal pregnancies. However, if you do get pregnant you will need to tell your doctor and midwife that you have donated a kidney. There is a risk that you could get high blood pressure when you are pregnant so your midwife and doctor will need to monitor you more closely.