A cat that snores while awake is producing a sound called stertor, a low-pitched snoring or snorting noise that happens during breathing. Unlike the occasional snore during a deep nap, snoring while awake almost always signals some degree of airway obstruction in the nose, throat, or the back of the mouth. The causes range from minor congestion to growths that need surgical removal, so identifying the pattern and any accompanying symptoms matters.
What Creates the Sound
Stertor is caused by air vibrating against soft, flexible tissue that’s partially blocking the upper airway. Think of it like the sound a person makes when snoring with a stuffy nose, except the cat is fully conscious. The obstruction sits somewhere between the nostrils and the back of the throat. Cats that make this sound while awake will typically snore during sleep too, but the reverse isn’t always true. Occasional sleep-only snoring can be normal, especially in certain breeds. Awake snoring indicates the blockage is significant enough to affect breathing even when the cat’s airway muscles are fully engaged.
A related but different sound, stridor, is higher-pitched and more of a whistle. Stridor points to narrowing closer to the voice box or windpipe, where the tissue is more rigid. If you’re hearing a low rumble or snort, that’s stertor. If it’s a thin, wheezy whistle, that’s stridor. Both warrant attention, but they point to different locations in the airway.
Flat-Faced Breeds and Built-In Obstruction
Persians, Exotic Shorthairs, British Shorthairs, and Scottish Folds are brachycephalic breeds, meaning their skulls are shortened front to back. The bone structure of their muzzle is compressed, but the soft tissue inside doesn’t shrink to match. The result is a cramped nasal cavity and partial obstruction of the throat and voice box from birth. In a survey of Persian and Exotic Shorthair owners, about 41% reported their cats snored during sleep and 42% described noisy breathing overall.
If you have a flat-faced cat, some degree of audible breathing may be their baseline. That said, “normal for the breed” doesn’t mean harmless. A flat-faced cat whose breathing noise worsens, who starts open-mouth breathing, or who tires easily during play may be progressing from mild to clinically significant obstruction.
Nasopharyngeal Polyps
One of the most common physical causes of sudden snoring in young cats is a nasopharyngeal polyp. These are noncancerous masses that grow in the upper airway, typically in the space behind the soft palate or inside the middle ear. They develop most often in kittens and cats under about a year old, though they can appear at any age.
A cat with a polyp feels like something is stuck in the back of its throat. When it tries to breathe through its nose, the mass blocks airflow and produces that characteristic stertorous sound. Other signs include nasal discharge, head shaking, difficulty swallowing, sneezing, and sometimes a sudden honking noise called reverse sneezing, where the cat seems to be trying to clear its throat. Polyps are treatable, usually through a procedure to pull or surgically remove the growth, and most cats recover well.
Chronic Nasal Inflammation
Cats that have had one or more upper respiratory infections, especially as kittens, can develop long-term inflammation in their nasal passages. This condition causes ongoing sneezing, nasal discharge, and noisy breathing. Over time, the inflammation damages the delicate structures inside the nose, and discharge accumulates instead of draining normally. That buildup partially blocks airflow and creates a snoring sound even when the cat is sitting upright and fully alert.
Environmental allergens can produce similar congestion. Pollen, grass, mold, mildew, and dust mites all trigger allergic responses in some cats. The reaction can include coughing, sneezing, wheezing, and nasal or eye discharge. Seasonal patterns are a clue: if the snoring gets worse in spring or fall, allergens are a likely contributor. Year-round triggers like dust mites and mold cause persistent symptoms.
Foreign Objects in the Nose
Grass awns are the most commonly reported foreign body found in cats’ nasal passages, though sewing needles also appear in veterinary literature with surprising frequency. A foreign object lodged in the nasal cavity or the back of the throat causes a sudden onset of snoring, snorting, pawing at the nose, and repeated swallowing attempts. Symptoms typically start abruptly and may worsen over the following days as inflammation builds around the object. Bad breath and nasal discharge often develop shortly after.
The key difference between a foreign body and other causes is the sudden start. If your cat was breathing silently yesterday and is snoring today, something may be physically stuck.
Growths and Tumors
Masses in the nasal cavity or throat can obstruct airflow the same way polyps do, but cancerous growths tend to appear in older cats rather than young ones. Nasal tumors typically cause progressive symptoms: the snoring gets gradually louder over weeks or months, often alongside bloody or discolored nasal discharge from one nostril. This pattern of slow worsening in an older cat is distinct from the sudden onset of a foreign body or the chronic, stable noisiness of a flat-faced breed.
Excess Weight
Overweight cats carry extra fat tissue around the neck and throat, which narrows the airway from the outside. This added pressure on the flexible tissues of the upper airway increases resistance to airflow and makes breathing audible. If your cat has gained weight recently and the snoring appeared around the same time, the two are likely connected. Weight loss alone can sometimes resolve the noise entirely.
How Vets Identify the Cause
The first step is usually a thorough examination of the mouth and back of the throat, ideally while the cat is awake so the vet can observe normal breathing dynamics. If the cause isn’t visible on exam, the next steps typically involve imaging. X-rays can reveal obvious masses or fluid buildup, while a CT scan provides detailed views of the nasal passages and skull. Endoscopy, where a tiny camera is passed through the nose or mouth, lets the vet directly see polyps, foreign objects, or inflammation. In some cases, a tissue biopsy is needed to distinguish between benign and cancerous growths.
Signs That Need Urgent Attention
Mild, stable snoring in an otherwise healthy cat can be monitored and brought up at your next vet visit. But certain breathing changes are emergencies. Open-mouth breathing in a cat is never normal and indicates serious respiratory distress. Other red flags include a visibly rapid breathing rate, panting, frequent coughing, extending the head and neck forward as if gagging, and a blue or purple tint to the gums or tongue. Cats in respiratory distress may lower their heads and stretch their bodies forward in a characteristic posture.
A cat showing any of these signs is at high risk and needs veterinary care immediately, not at the next available appointment. Breathing problems in cats can deteriorate quickly, and the window for effective treatment narrows fast.