Perichondritis is a condition characterized by pain, swelling and purulent discharge from the external ear, which may progress to a deformity of the pinna. The presence of co-morbidities such as diabetes mellitus may aggravate the situation. The main aetiological agent is Pseudomonas aeruginosa and treatment consists of antibiotics combined with surgical drainage of the ear. We present the case of a diabetic patient with recurrent perichondritis of the pinna treated with hyperbaric oxygen therapy, with successful healing. Hyperbaric oxygen therapy has proved beneficial as adjunctive therapy of lesions in diabetic patients with foot ulcers, acting in the regeneration of intracellular free radicals and promotion of wound-healing factors. Thus, owing to its mechanisms of action, its effect on other injuries such as perichondritis in diabetic patients may be beneficial and lead to improvement.433166167