What I’ve Learned as a Practicing Veterinarian
I’ve been practicing small-animal veterinary medicine for over a decade, and Kirkland Signature dog food is one of those brands that comes up whether I bring it up or not.
Owners ask about it during wellness visits, weight-loss consults, and sometimes during uncomfortable conversations after a dog develops chronic digestive issues. The question almost always starts the same way: “Doctor, who actually makes Kirkland dog food?”
That’s a fair question. You’re trusting a company you can’t see with something your dog eats every day.
The Short Answer, Based on Real-World Vet Experience
Kirkland Signature dog food was made by Diamond Pet Foods, a large U.S.-based manufacturer that produces food for several well-known brands. Costco owns the Kirkland label, but it doesn’t operate its own pet food factories. Instead, they contract manufacturing to Diamond and set the specifications for formulation, sourcing, and quality standards.
I first learned this not from a press release, but from a frustrated client several years ago who brought in a bag with a manufacturing code after a recall scare. Tracing that code led straight back to Diamond’s facilities. Since then, I’ve confirmed the same information repeatedly through distributor documentation and manufacturer disclosures.
What Diamond Pet Foods Means in Practical Terms
Diamond Pet Foods has been around for decades. They operate multiple manufacturing plants in the U.S. and produce food not only for Kirkland, but also for brands like Taste of the Wild and Diamond Naturals. From a veterinary standpoint, that matters for two reasons: scale and consistency.
I’ve treated dogs that did very well on Diamond-manufactured diets for years without issue. One Labrador patient of mine, a heavy-set senior with joint problems, stayed on Kirkland’s adult formula for most of his later life and maintained stable weight and bloodwork, which is more than I can say for some boutique brands his owner tried before that.
That said, scale cuts both ways.
Recalls and What I’ve Seen Firsthand
Any honest vet will acknowledge that Diamond Pet Foods has had recalls in the past. I’ve lived through them in real time. I remember one spring when half my afternoon appointments involved worried Costco shoppers holding phones with recall alerts pulled up. We spent more time calming nerves than treating symptoms.
What stood out to me wasn’t panic-level illness — I didn’t see dogs collapsing left and right — but mild gastrointestinal upset in a handful of cases. Loose stools, brief vomiting, nothing catastrophic. That doesn’t excuse recalls, but it does put the real-world impact into perspective.
In my experience, no large manufacturer with wide distribution has a spotless record. The difference is how quickly issues are addressed and how transparent the response is. Diamond has improved noticeably in that area over the years.
Why Kirkland Dog Food Is So Affordable
Clients often assume a lower price equals lower quality. That’s not how Kirkland works.
Costco operates on high volume and low margins. They don’t spend heavily on flashy marketing or celebrity endorsements. The money goes into sourcing ingredients and manufacturing contracts rather than ad campaigns. I’ve reviewed Kirkland ingredient lists alongside much pricier foods, and nutritionally, many of them hold up better than people expect.
I once had a client switch from a trendy, expensive grain-free brand to Kirkland after their dog developed chronic diarrhea. Within weeks, the issue was resolved. That wasn’t magic — it was a simpler formulation with better digestibility for that specific dog.
Common Mistakes I See Owners Make With Kirkland
One mistake I see repeatedly is assuming all Kirkland formulas are interchangeable. They’re not.
Some dogs do well on the chicken-based formulas. Others don’t tolerate them at all. I’ve had multiple cases where skin itching cleared up simply by switching within the Kirkland line, not abandoning the brand altogether.
Another issue is overfeeding. Kirkland’s calorie density can be higher than some grocery-store foods. I’ve seen weight creep up quietly over six months because owners didn’t adjust portions after switching.
Would I Recommend Kirkland Signature Dog Food?
In many cases, yes — with conditions.
I’m comfortable recommending Kirkland dog food for healthy adult dogs without complex medical needs, especially for owners who want a reliable, affordable option from a well-known manufacturer. For dogs with kidney disease, severe allergies, or gastrointestinal disorders, I usually steer owners toward prescription or limited-ingredient diets instead.
I feed my own dog a diet manufactured by a large, established company for the same reason I recommend it to clients: predictable formulation, consistent quality, and fewer surprises.
The Bottom Line From the Exam Room
Diamond Pet Foods makes Kirkland Signature dog food under Costco’s private-label standards. It’s not a mystery brand, and it’s not a bargain-bin experiment. Like any mass-produced food, it has strengths and limitations, and it won’t be perfect for every dog.
What matters most —and what I remind owners in almost every nutrition conversation —is not the logo on the bag—it’s how your individual dog responds over time. Appetite, stool quality, skin condition, and energy levels. Those signs tell me far more than marketing claims ever could.
