Exercising is one of the three cornerstones in the treatment of lymphedema together with contention mechanisms and lymphatic drainage. The aim of the current study was to evaluate a new method of mechanic lymphatic drainage. Volumetric reductions were evaluated after passive exercises in 25 patients with arm lymphedema resulting from breast cancer treatment. Their ages ranged between 42 and 86 years old. All patients were submitted to one-hour sessions using the RAGodoy electromechanical apparatus which performs from 15 to 25 elbow bending and stretching exercises per minute. Volumetry, using the water displacement technique, was performed before and after the sessions. The paired t-test was employed for statistical analysis with an alpha error of less than 5% being considered acceptable. The reduction in volume was significant (P-value < 0.001) with a mean initial volume of 2026.4 and final volume of 1967.2 giving a mean loss of 59.2 mL. The RAGodoy apparatus was efficient to reduce the volume of lymphedematous arms and is an option for the treatment of lymphedema.