Where are dogs kidneys?

Knowing where a dog’s kidneys are and what they do is one of those practical bits of anatomy that pays off quickly: it helps owners spot trouble sooner, ask the right questions at the clinic, and make everyday choices that protect long-term health.

How knowing where the kidneys are helps you protect your dog

As a veterinarian I often see owners who know their dog’s habits and habits’ changes long before a blood test does. Knowing the general location and vulnerabilities of the kidneys makes those observations more useful. In health checks and emergencies, being able to say “my dog started drinking and peeing more two days ago” and to point where the dog seems sore or swollen can change the triage level at a clinic.

When your vet reads lab work, x-rays, or an ultrasound, they may describe abnormalities relative to the kidneys’ position. If you understand that the kidneys sit behind the abdominal organs along the spine by the last ribs, you can better interpret what the clinician is explaining—whether a shadow on an x-ray is near a kidney or whether an ultrasound image is showing one of the kidneys versus a nearby structure.

Knowing anatomy can also change care decisions: for example, recognizing that a hard lump under the far side of the last ribs could be an enlarged kidney rather than a mass in the intestine may prompt faster diagnostics. Finally, being informed helps you advocate for your dog—asking for specific tests or imaging when kidney disease is plausible, and understanding why a specialist referral might be appropriate.

Kidney location in dogs — the short answer

Dogs have two kidneys located retroperitoneally—behind the abdominal cavity and in front of the muscles along the back. Each kidney lies near the spine under the last few ribs. The left kidney is usually slightly more cranial (closer to the head) than the right, which is often a useful point when a vet describes side-to-side differences on imaging.

Size varies considerably with body size and breed but in many adult dogs a kidney may be roughly the size of a fist to the size of an open palm. In smaller or toy breeds they are proportionally smaller; in large breeds they are larger. Because the kidneys sit under the ribcage and deep in the body, they are not often easy to feel during a routine exam unless they are enlarged or the dog is unusually thin.

How a dog’s kidneys work: functions and essentials

The kidneys are fundamentally filters and regulators. They are the primary organs that remove nitrogenous waste—by converting blood-borne waste into urine—so maintaining the blood’s chemical balance. Loss of filtering function can allow toxins to build up, and that is why early changes in appetite, drinking, and urination often precede more obvious illness.

Beyond waste removal, kidneys concentrate urine and control the body’s fluid and electrolyte balance. They help regulate sodium, potassium, and acid–base balance, so dysfunction may cause abnormal blood potassium or changes in acid levels that affect the heart and muscles.

Kidneys also make hormones. They release erythropoietin, which stimulates red blood cell production, and play a role in the renin–angiotensin–aldosterone system (RAAS), which helps control blood pressure and fluid volume. They also activate vitamin D into a form that helps regulate calcium; disturbances here can affect bones and calcium metabolism over time. Because of these varied roles, kidney disease rarely affects only urine production; it tends to produce systemic signs.

How kidney position affects function and injury risk

The kidneys’ placement behind the abdominal cavity and under the ribs has several consequences. The rib cage and adjacent back muscles offer protection against blunt trauma; when a dog falls or is struck, the bones and musculature are a first line of defense. That same placement means severe trauma to the back or side can still injure a kidney, especially in high-speed collisions or bites.

The kidneys receive a large, direct blood supply from branches of the aorta and drain into the caudal vena cava. Their proximity to these major vessels facilitates the high blood flow needed for filtration but also means that systemic blood pressure and dehydration can quickly change kidney perfusion. In practice, dehydration or shock often shows up as reduced kidney function before other organs show obvious signs.

Because they sit deep and behind the intestines, palpation is limited; many clinicians rely on imaging—ultrasound being the most informative—for size, shape, and blood flow. Surgical access is also influenced by position: some kidney surgeries are approached through the flank or by opening the abdomen depending on whether the surgeon needs to reach the left or right kidney, and both approaches carry specific risks related to nearby organs and blood vessels.

When kidney problems most often appear — age and triggers

Age is one of the clearest risk factors. Chronic kidney disease becomes more common as dogs reach senior years and is often progressive and slow to appear. Acute problems can occur at any age, frequently after exposure to toxins or severe dehydration.

Toxins that may cause sudden kidney injury include ethylene glycol (antifreeze), certain over-the-counter medications and prescription drugs when given incorrectly, and some foods—grapes and raisins are recognized triggers for acute kidney injury in dogs, though susceptibility varies. Severe infections, heat stress with lasting dehydration, and low blood pressure during anesthesia or trauma can also precipitate acute damage.

Some breeds appear more predisposed to particular renal issues; for example, polycystic kidney disease or congenital abnormalities may cluster in certain lines. Concurrent illnesses—such as heart disease or endocrine disorders—can further strain kidney function and hasten clinical signs.

Symptoms that should make you call the vet

• Changes in urination: increased or decreased frequency, larger or smaller volumes, blood in urine, or strong/foul odor.
• Lethargy, vomiting, poor appetite, persistent weight loss or failure to gain weight.
• Excessive thirst, bad breath with a chemical or ammonia-like smell (uremic breath), or mouth sores and ulcers.
• Visible abdominal pain or swelling, disorientation, wobbliness, or collapse—these can indicate severe electrolyte disturbances or advanced kidney failure and warrant immediate care.

If you suspect a kidney issue: immediate steps for owners

• Observe and record: note when symptoms started, how they have changed, what the urine looks like, any possible toxin exposure, and recent medications. Clear notes help the vet form a timeline.
• Provide water and limit stress: make fresh water available at all times and keep your dog calm. Do not withhold water unless a veterinarian instructs otherwise.
• Collect a urine sample if safe: a midstream sample in a clean container is ideal. If your dog will allow, use a shallow bowl or catch urine on a clean plastic container. Refrigerate the sample and bring it to the clinic within a few hours if possible.
• Bring a list of medications, supplements, and possible toxin access, and go to your regular vet or an emergency clinic promptly. If your dog is vomiting repeatedly, lethargic, collapse-prone, or having seizures, seek emergency care right away.

Making your home and routines kidney-friendly

Prevention and early detection are often about environment and routine. Keep water available at all times and encourage regular potty breaks; animals that are allowed to hold urine for long periods may be at higher risk of urinary issues that secondarily affect the kidneys.

Store foods and household chemicals out of reach. Antifreeze and certain human medications are especially dangerous. I typically advise clients to treat cabinets and garages as off-limits and to use childproof latches if necessary.

Diet and weight management matter. A balanced diet appropriate for the dog’s life stage, breed, and any existing conditions helps reduce strain on kidneys over time. Regular vet checks with basic bloodwork and urine testing as dogs age will often find early changes when intervention can slow progression.

Training your dog to accept a carrier, sit calmly for handling, and tolerate brief restraint makes vet visits less stressful and faster. Dogs that are calm are easier to examine, more likely to allow urine collection, and less likely to injure themselves during transport.

Helpful tools and products for kidney monitoring and care

A continuous-flow water fountain can encourage drinking and keeps water fresher than a stagnant bowl. Spill-proof and raised bowls help older dogs drink more comfortably. Home urine test strips for specific measures (such as glucose, protein, and pH) can provide quick snapshots between vet visits, though they do not replace professional analysis.

A simple pet scale is invaluable for tracking weight loss, which is often subtle but important. Urine sample collection kits—reusable shallow dishes, clean disposable cups, or commercial sample collection kits—make it easier to bring a fresh sample to the clinic. Finally, secure storage containers for medications and chemicals reduce accidental exposures.

Managing a diagnosis: realistic care for dogs with kidney disease

If kidney disease is diagnosed, the approach depends on whether it is acute or chronic. Acute kidney injury may require hospitalization for fluids, supportive care, and treatment of the underlying cause; many dogs improve if the cause is identified and treated promptly. Chronic disease is managed long term with dietary changes, blood pressure control, phosphate binders when needed, and close monitoring. I typically recommend serial bloodwork, urine tests, and weight checks every few months for dogs with chronic disease.

Home care focuses on consistent medication, maintaining hydration, monitoring appetite and urination, and noticing subtle changes early. If your dog develops sudden worsening—more vomiting, collapse, fainting, or seizures—treat that as an emergency. With attentive care and the right medical support many dogs with kidney disease maintain a good quality of life for months to years.

References and further reading

• Merck Veterinary Manual: Acute Kidney Injury in Dogs and Cats
• American Veterinary Medical Association (AVMA): Chronic Kidney Disease in Dogs—Client Information and Guidance
• John E. Gracey, “Canine and Feline Nephrology and Urology”, in BSAVA Manual of Canine and Feline Nephrology and Urology
• Cornell University College of Veterinary Medicine: Kidney Disease in Dogs — Clinical Resources and Owner Guides
• Journal of Veterinary Internal Medicine: “Management of Chronic Kidney Disease in Dogs” (review article)