Necrotising fasciitis is a rare but potentially fatal disease. It is even more unusual as a primary disease of the breast. Surgical treatment is required in order to gain control over the spreading infection and mastectomy is reported to be the most common procedure. We report the first case of an otherwise healthy woman exhibiting a primary necrotising fasciitis of the breast, which was treated combining conservative surgery with hyperbaric oxygen (HO) and negative pressure wound therapy (NPWT). A 39-year-old woman presented to the emergency room with fever and swelling of her right breast. The physical examination showed oedema and erythema of the breast, with bluish blisters on the lower quadrant. Ultrasound and CT scans showed diffuse oedema of the entire right breast, with subdermal gas bubbles extending to the fascial planes. Few hours later the necrotic area extended regardless an IV antibiotic therapy; a selective debridement of all breast necrotic tissue was performed and repeated 7 days later. The HO was started immediately after the first surgery and repeated daily (2·8 Bar, 120 min) for 18 days and then a NPWT (120-135 mmHg) was applied. Forty-five days after the last debridement, the breast wound was covered with a full-thickness skin graft. Several months later, an excellent cosmetic result was observed. This is the first case of primary necrotising fasciitis of the breast treated associating HO and NPWT to surgical debridement only; this combination resulted in a complete recovery with the additional benefit of breast conservation. Such result is discussed in light of the available literature on the treatment of primary necrotising fasciitis of the breast.