Children's sleepwear in sizes 0–14 must comply with CPSC flammability standards under 16 CFR Parts 1615 and 1616. Garments must either be made from inherently flame-resistant fiber or be treated with a flame retardant. Importers are responsible for ensuring compliance before the goods enter commerce, and testing records should be maintained.

A sleep shirt is generally classified as a nightdress if it is marketed, labeled, and designed for sleepwear use. CBP looks at labeling, retail packaging, and design features. If the garment is sold as general casualwear without sleepwear designation, it may be reclassified as a shirt or jersey under a different heading.