Diane Arbus was known for her photographs of outsiders and people on the fringes of society. She often shot with a Rolleiflex medium format twin-lens reflex that provided a square aspect ratio and a waist-level viewfinder. The viewfinder allowed Arbus to connect with her subjects in ways that a standard eye-level viewfinder did not.
Identical Twins depicts two young twin sisters, Cathleen and Colleen Wade, standing side by side in matching corduroy dresses, white tights, and white headbands in their dark hair. Both stare into the camera, one slightly smiles and the other slightly frowns. The parallelism and haunting nature of the photo has been the subject of many essays. The photo has been said to sum up Arbus’ vision. Biographer Patricia Bosworth said, "She was involved in the question of identity. Who am I and who are you? The twin image expresses the crux of that vision: normality in freakishness and the freakishness in normality.
The twins were seven years old when Arbus spotted them at a Christmas party for twins and triplets. The twins' father once said about the photo, "We thought it was the worst likeness of the twins we'd ever seen."
The photo has also inspired other art and is said to be echoed in Stanley Kubrick's film The Shining, which features twins in an identical pose. It is also briefly referenced in Harmony Korine's Gummo.
Identical Twins is tenth on the list of most expensive photographs having sold in 2004 for $478,400.