Fifteen patients with postmastectomy lymphedema of the arm were treated with the Wright linear pump, a programmable, gradient pressure, sequential, intermittent compression pump. The group comprised volunteers in whom conservative measures had failed. This is a phase II trial to determine the efficacy of the pump. All patients had subjective improvement. Objectively, all showed a reduction in edema, but this was of variable degree and depended on the amount of pre-existing lymphedema in the arm. The Wright linear pump is easy to use and treatment was well tolerated. No fluid overload occurred due to treatment and no other medical problems were encountered. The Wright linear pump seems more effective than other pneumatic intermittent compression pumps available.