The Costume Collection consists of more than 50,000 objects dating from the mid-18th century to the present. The strength of the collection lies in its 20th-century holdings and, particularly, in couture and ready-to-wear women's clothing. The collections are currently being computerized to facilitate research.
- The costume collection includes fashion by designers such as Azzedine Alaïa, Balenciaga, Chanel, Comme des Garçons, Dior, Galanos, Halston, Charles James, Norell, Paul Poiret, Yves Saint Laurent and Vivienne Westwood.
- The Halston Archives and Study Room hold designs, patterns, and related records documenting this important designer's life work.
- The menswear collection features some 2,000 garments ranging from formal to activewear, including suits, coats, vests, and uniforms.
- Also included are swimwear, lingerie, outerwear, and knitwear.