Background/purpose: The diagnosis of the Ehlers–Danlos syndrome (EDS) is primarily clinical. Clinical signs result from modifications of the rheological properties of the skin: thickness, extensibility and hydration. Our main objective was to demonstrate what skin biometry can contribute to the diagnosis and evaluation of the different types of EDS. Methods: Forty-one patients clinically diagnosed with EDS were paired by age and sex to 41 healthy subjects with no known dermatologic disease, in particular connective tissue diseases. We measured skin thickness, extensibility, hydration and sebum secretion by skin ultrasonography, use of a Cutometer®, a Corneometer® and a Sebumeter®. Results: The skin is thinner in all three disease types (classical, hypermobility and vascular). It is more extensible only in the classical type, and more hydrated and fatty in the hypermobility type. Conclusion: Non-invasive measurement of skin thickness and elasticity are quantitative parameters that can be used to better diagnose EDS. Moreover, the sebaceous rate can help to diagnose the hypermobility type whereas the immediate retraction distinguishes the classical form from vascular and hypermobile types.