Diapering · Last checked Sep 30, 2026
Kirkland Signature Diapers (Costco)
Verdict
Once an award winner, BabyGearLab no longer recommends it after a 2024 manufacturer change. PFAS indicators were detected inside the diaper in Mamavation's test.
~$0.33/diaperCostco
What parents and testers say
Recurring praise
- Cheap in bulk
Recurring complaints
- Reformulated in 2024; no longer recommended by testers
- PFAS indicators detected
Our summary of patterns across the reviews and threads linked below. Not quotes.
Materials & safety check
!PFAS screenOrganic fluorine detected (26 ppm inside) in Mamavation's 2023–24 test
When to buy it
Before birth
1 pack of newborn size only
Weeks 2–6
Most babies move to size 1
Ongoing
Buy in bulk once you know the fit works
Consider instead: Hello Bello for a similar price.
Sources
- BabyGearLab: Best disposable diapers (lab tests)
- Mamavation: Diapers tested for indications of PFAS (2023–24)
Spot something wrong or out of date? Email hello@cradlescore.com and we'll recheck it.