A 30-year-old woman developed massive bilateral breast hypertrophy (MBH) during her third pregnancy. Both breasts became very heavy and painful and more than tripled in size. The skin became oedematous and red, and subsequently ulceration, necrosis and bleeding occurred. The patient was bedridden because of the enormous size of the breasts. Prolactin, oestrogen and steroid levels were normal. Hormonal manipulation with bromocriptine, tamoxifen and cortico-steroids had no effect on the progression of the MBH. A caesarean section performed at the 32nd week arrested the MBH and caused a significant reduction in breast size. Later a reduction mammoplasty was performed and more than 10 kg of breast tissue was excised.