Introduction to your kidneys

Learn where your kidneys are located in your body, what they do, what happens if they stop working and how you can keep your kidneys healthy.

kidneys purple
Diagram of kidneys, ureter and bladder

Your kidneys are vital organs. This means you cannot survive without them. They filter waste from your blood and do other important jobs, such as helping control your blood pressure and make red blood cells. Most people are born with two kidneys, but some people are born with just one. You can live with one healthy kidney.

Where are my kidneys located and what do they look like?

Your kidneys are bean-shaped organs located near the middle of your back, one on either side of your spine. Each is about the size of a fist. Your kidneys are part of your urinary tract, which is the group of organs that make urine (i.e. pee) and remove it from your body. The urinary tract includes your kidneys, ureters, bladder and urethra.

Diagram of a healthy kidney vs a damaged kidney

What do my kidneys do?

Your kidneys filter all the blood in your body several times a day and remove about half a gallon of extra fluid and waste products. These make up your urine. Your urine travels through your ureters to your bladder and leaves your body through your urethra. The filtered blood returns to your bloodstream through your veins.

Your kidneys do many other important jobs, such as helping to:

Control your blood pressure
Keep your bones healthy
Make red blood cells
Manage your body's vitamin D levels

Regulate certain electrolytes in your body, such as sodium, calcium and potassium.

What happens if my kidneys are damaged?

If your kidneys are damaged and do not work as they should, extra fluid and waste flow back into your bloodstream instead of leaving your body as urine. This can cause fluid and toxic waste to build up in your body, which can affect organs including your brain, heart, lungs and bones.

What causes kidney damage?

There are several causes of kidney damage:

  • Chronic kidney disease (CKD)
  • A kidney injury, such as from an accident or a sports injury
  • Acute kidney injury

Chronic kidney disease (CKD)

In the early stages of CKD, many people do not have any symptoms and may not know that their kidneys are damaged. When kidney disease becomes advanced, you may notice symptoms, such as:

Who can get CKD?

Anyone can get CKD, but some things will raise your chances, such as being of older age or having diabetes, high blood pressure or a family history of kidney disease. If you have any risk factors for CKD, talk to your doctor about getting tested.

Can CKD be cured?

There is no cure for CKD, which means that any damage to your kidneys cannot be reversed. However, if CKD is diagnosed early, there is a lot you and your doctors can do to slow down damage to your kidneys, such as making healthy lifestyle changes. Even small changes can make a big difference in keeping your kidneys working for as long as possible.

Acute kidney injury

Sometimes, your kidneys can stop working very suddenly — within two days or less. This is called acute kidney injury (or sometimes acute renal failure). It can happen if there is not enough blood flowing to your kidneys. In this case, kidney damage is not always permanent: if it is treated right away, your kidneys may recover to full or nearly full function.

What happens if my kidneys fail?

If your kidneys fail, that means they have completely stopped doing their job to filter waste from your blood. Kidney failure is also called end-stage renal disease. Waste may build up in your blood and cause health problems, such as: 

If this happens, you will need to start dialysis or have a kidney transplant to live.

How can I help keep my kidneys healthy?

The best way to take care of your kidneys is to keep a healthy lifestyle, which includes:

  • Make healthy meal choices: Follow a kidney-friendly food plan that is low in salt, fat and sugar and includes lots of fruits and vegetables.
  • Be active for at least 30 minutes on most days of the week — this can be anything from walking or riding a bike to swimming or dancing.
  • If you have high blood pressure or diabetes, follow your treatment plan to keep your blood pressure or blood sugar within your target range.
  • Quit smoking or using tobacco.
  • Keep a healthy weight — talk with your doctor about what a healthy weight is for you.

Your donation directly supports the fight against kidney disease

For 22 consecutive years Charity Navigator™ has rated us a Top Nonprofit. Your donations allow us to help more people than any other kidney organization – from making 150 kidney transplants possible every month to delivering financial relief to 1 in 7 dialysis patients. We also fund clinical research, provide financial assistance for kidney patients affected by natural disasters, and support a National virtual pediatric camp and a Kidney Health Coach community program.